Effects of an oral androgen on muscle and metabolism in older, community-dwelling men

E. Todd Schroeder1, Atam Singh2, Shalender Bhasin2, Thomas W. Storer2, Colleen Azen1, Tina Davidson2, Carmen Martinez1, Indrani Sinha-Hikim2, S. Victoria Jaque1, Michael Terk1, and Fred R. Sattler1

1 Departments of Medicine, Radiology, and Biokinesiology, Keck School of Medicine, University of Southern California, Los Angeles 90033; and 2 Division of Endocrinology, Metabolism, and Molecular Medicine, Charles Drew University School of Medicine, Los Angeles, California 90275


    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

To determine whether oxymetholone increases lean body mass (LBM) and skeletal muscle strength in older persons, 31 men 65-80 yr of age were randomized to placebo (group 1) or 50 mg (group 2) or 100 mg (group 3) daily for 12 wk. For the three groups, total LBM increased by 0.0 ± 0.6, 3.3 ± 1.2 (P < 0.001), and 4.2 ± 2.4 kg (P < 0.001), respectively. Trunk fat decreased by 0.2 ± 0.4, 1.7 ± 1.0 (P = 0.018), and 2.2 ± 0.9 kg (P = 0.005) in groups 1, 2, and 3, respectively. Relative increases in 1-repetition maximum (1-RM) strength for biaxial chest press of 8.2 ± 9.2 and 13.9 ± 8.1% in the two active treatment groups were significantly different from the change (-0.8 ± 4.3%) for the placebo group (P < 0.03). For lat pull-down, 1-RM changed by -0.6 ± 8.3, 8.8 ± 15.1, and 18.4 ± 21.0% for the groups, respectively (1-way ANOVA, P = 0.019). The pattern of changes among the groups for LBM and upper-body strength suggested that changes might be related to dose. Alanine aminotransferase increased by 72 ± 67 U/l in group 3 (P < 0.001), and HDL-cholesterol decreased by -19 ± 9 and -23 ± 18 mg/dl in groups 2 and 3, respectively (P = 0.04 and P = 0.008). Thus oxymetholone improved LBM and maximal voluntary muscle strength and decreased fat mass in older men.

oxymetholone; androgen therapy; older men; sarcopenia; lean body mass


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

AGING IN HUMANS IS CHARACTERIZED by a number of anatomic and physiological changes, including the progressive loss of muscle mass (sarcopenia), which contributes to the sequential loss of voluntary skeletal muscle strength and physical function (1, 3, 12, 17, 22). When severe, these outcomes may result in disability, dependency, and depression (39, 41). At the same time, aging is associated with increased fat mass, particularly central adiposity, which increases the risk for insulin resistance, hypertension, dyslipidemia, impaired fibrinolysis, and the occurrence of gallstones (42). Cross-sectional (2, 35, 52) and longitudinal (20, 36) studies are in agreement that total and free testosterone concentrations decline with advancing age in men, although a causal relationship between levels of testosterone and changes in body composition, skeletal muscle strength, and metabolism has not been well established during aging. However, serum bioavailable testosterone concentrations have been shown to correlate with skeletal muscle mass and muscle strength in both African-Americans and Caucasians (4, 40). Results from another study suggest that free testosterone levels are also closely related to muscle mass in women during chronic illness (19).

Although a number of studies are in agreement that testosterone supplementation in healthy, young, hypogonadal men increases fat-free mass (6, 9, 24, 49, 56, 57), muscle size (6), and strength (6, 57), the effects of testosterone supplementation on muscle mass and performance have been less clear in older men (26, 37, 46, 50, 52, 53). Although several studies have reported increases in fat-free mass following testosterone replacement in older men with low or low normal testosterone concentrations (25, 50, 52), one study did not find any change in fat-free mass (46). Supporting the increase in fat-free mass is evidence suggesting that androgen supplementation increases synthesis of myofibrillar proteins in older persons (13, 55). However, the effects of testosterone supplementation on muscle strength in this population have been inconsistent (46, 50). On the basis of this background, we hypothesized that a course of androgen supplementation would increase muscle mass and maximum voluntary strength in older men at risk for sarcopenia. We also hypothesized that this intervention would decrease central adiposity (32, 33) and that changes in muscle mass, strength, and adipose tissue would be dose related on the basis of our recent studies in younger men (7).

To test these hypotheses, we conducted a double-blind, placebo-controlled, proof-of-concept study by use of a convenient-to-administer potent oral androgen. The results indicated that muscle and adipose tissue in older individuals are responsive to supplemental androgen therapy and that adaptations in lean body mass (LBM) may change in a dose-related manner.


    METHODS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Study Population

Men 65-80 yr of age were recruited from the Los Angeles communities surrounding the University of Southern California Health Sciences Campus and Charles Drew University of Medicine and Science. To be eligible for the study, subjects had to have a body mass index (BMI) <36 kg/m2, blood pressure <160/95 mmHg, prostate-specific antigen (PSA) <4.1 ng/ml, serum hematocrit <50%, alanine aminotransferase (ALT) less than three times the upper limit of normal (ULN), and serum creatinine <2 mg/dl. Subjects with untreated endocrine abnormalities (e.g., diabetes, hypothyroidism), active inflammatory conditions, or cardiac problems in the preceding 3 mo (heart failure, myocardial infarction, or angina) were excluded. An incremental treadmill exercise test with 12-lead electrocardiographic and blood pressure monitoring was administered before resistance exercise testing to identify exercise-induced ischemia, abnormalities in cardiac rhythm, or abnormal blood pressure responses. The institutional review boards of the Los Angeles County-USC Medical Center and Charles Drew University approved this study. All subjects provided written, informed consent.

Safety Monitoring

Complete blood counts, comprehensive chemistries with tests of renal and hepatic function, and prostatic specific antigen were measured at baseline and during treatment weeks 6 and 12. Liver test panels were also obtained at weeks 3 and 9 in addition to the aforementioned time points.

Intervention

The study was a two-center, investigator-initiated, dose-ranging, double-blind, placebo-controlled trial. Subjects were randomized to receive oral doses of placebo, 50 mg of oxymetholone, or 100 mg of oxymetholone daily for 12 wk. To achieve blinding, the subjects received two placebo tablets, one placebo plus one 50-mg oxymetholone tablet, or two 50-mg oxymetholone tablets. Adherence was monitored by pill counting at each study visit.

Dual-Energy X-Ray Absorptiometry

Whole body dual-energy X-ray absorptiometry (DEXA) scans [Hologic QDR-4500, version 7.2 software (Waltham, MA) at both institutions] were performed at baseline and study week 12 to assess lean tissue and fat mass. Two experienced technicians performed and analyzed the scans, one at each of the respective test sites. The coefficients of variation (CV) in study subjects for repeated measures of lean tissue and fat were <1%.

Regional Measures of Body Composition

Regional body composition was determined at only one of the centers. Change in appendicular (extremity) LBM and in trunk fat were assessed by DEXA. Change in muscle cross-sectional area (CSA) was assessed by magnetic resonance imaging (MRI). The MRI scans were performed using a 1.5-Tesla GE Signa-LX scanner, with the body coil serving as both transmitter and receiver. Nine axial images of the thigh were obtained after a T1-weighted coronal scout image using T1-weighted TR/TE 300/TE. The slice thickness was 7.5 mm with a 1.5-mm gap. The field of view was 24 × 24 cm with a 254 × 128 matrix. One signal average was used.

To determine muscle CSA, the juncture of the proximal and middle thirds of the femur was chosen for analysis, as greater relative increases in CSA of the proximal quadriceps have been reported following resistance training (38). Areas of intramuscular fat, bone, connective tissue, and blood vessels were subtracted (4.4 Gyroview, version 2.1-2, Philips Medical Systems) before calculation of muscle areas. Setting threshold values based on signal amplitude allowed the various tissues to be segmentalized. Once the threshold values were established, lean tissue (muscle, connective tissue, and blood vessels) and fat displayed signal strength above and below the threshold, respectively. Area of the femur was removed manually by digitizing the circumference of the bone and deleting this area with the software. The same blinded investigator (E. T. Schroeder) performed the analyses, and the CV for repeated measures was <1%.

Muscle Strength Evaluation

Before strength testing, subjects warmed up on a cycle ergometer or by walking for 5 min. Strength was determined for the bilateral leg press, seated biaxial chest press, and lat pull-down exercises. Subjects performed five repetitions of the test exercises at 50 and 75% of their projected maximal strength on Keiser A-300 pneumatic equipment (at both test centers) or on lat pull-down machines. The lat pull-down machines used at the two sites had different pulley systems. Therefore, changes in strength were reported as relative (%) change. Maximum voluntary muscle strength was determined by the one-repetition maximum (1-RM) method (14), defined as the greatest resistance that could be overcome through the range of motion using proper technique. The 1-RM was determined for all exercises twice within 1 wk before initiating study therapy to accommodate familiarization and learning of the testing procedures. The greatest 1-RM measured for each exercise during the two testing sessions was used as the baseline value for maximal voluntary muscle strength. The 1-RM for these exercises was assessed again during study week 12.

Nutritional Assessment

Subjects recorded dietary intake on three consecutive days, including two weekdays and one weekend day in the week before baseline and study week 12. Subjects were counseled that the days should be chosen to include usual activities and typical eating patterns. The same licensed nutritionist reviewed all dietary entries with the subjects. This information was entered into the Nutritionist V software (First Data Bank, San Bruno, CA) and analyzed for total energy intake, macronutrients, and types of fat. Subjects were counseled not to change their routine dietary habits during the course of the study.

Measurement of Fasting Serum Lipids

Blood was collected after a 14-h overnight fast at baseline and during study week 12 for plasma lipids. Plasma was analyzed for total cholesterol, HDL-cholesterol, and triglycerides by means of the Ortho/Vitros DTII system (Ortho Diagnostics, Rochester, NY) in the University of Southern California General Clinical Research Center Core Laboratory (58). Plasma lipid concentrations in baseline and week 12 samples for each subject were run in the same assay to eliminate the effects of interassay variation. The CVs for the three lipids were <4.5, <4.4, and <3.0%, respectively. LDL-cholesterol was calculated using the Friedewald equation (15).

Measurement of Fasting Blood Sugar and Insulin

Blood was collected after a 14-h overnight fast in prechilled heparinized tubes. Plasma was removed and frozen within 10 min of collection. Glucose was measured by the glucose oxidase method (YSI model 2300 STAT PLUS glucose analyzer, YSI, Yellow Springs, OH) with a CV of 2.5%. Insulin was measured by radioimmunoassay (Linco Research, St. Charles, MO), which had <0.2% cross-reactivity with proinsulin and a CV of 3.2%. Glucose and insulin concentrations from baseline and 12-wk tests for each subject were measured in the same assay to eliminate the effects of interassay variation.

To assess for insulin resistance, fasting insulin, the homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI) were calculated, since these measures have been correlated with insulin sensitivity by the hyperinsulinemic euglycemic clamp (23, 28, 29). HOMA-IR is calculated as [(If) × (Gf)]/22.5, where (If) is the fasting insulin level (µU/ml) and (Gf) is the fasting glucose level (mmol/l). QUICKI is calculated as 1/[log (If) + log (Gf)] (23).

Measurements of Testosterone

Total testosterone concentrations were measured by RIA, using iodinated testosterone as tracer (5, 7) (no. 07-189102; ICN Biomedical, Costa Mesa, CA). This assay has a sensitivity of 0.44 ng/dl and intra- and interassay CVs of 9.1 and 7.5%, respectively. Free testosterone levels were measured by equilibrium dialysis (47, 48). Two hundred microliters of serum were placed in the inner dialysis chamber and dialyzed against 2,400 µl of dialysis buffer that approximates protein-free human serum. Dialysis was performed overnight for 16 h at 37°C. The free testosterone concentration in the dialysate was measured by RIA with the use of 125I-labeled testosterone. The sensitivity of the free testosterone assay was 0.6 rho g/ml, and the intra- and interassay CVs were 4.2 and 12.3%, respectively. We did not test for total and free testosterone levels at the end of the 12-wk treatment period, because semisynthetic androgens including oxymetholone cross-react in these assays for testosterone. Serum luteinizing hormone (LH) and sex hormone-binding globulin (SHBG) concentrations were measured by immunofluorometric assays (5, 7).

Statistical Considerations

On the basis of variance of body composition in different ethnic and racial populations (27) and the standard deviation (SD) of change in response to an anabolic agent used in one of our previous studies (44), we hypothesized that a 3.0-kg increase in total LBM with oxymetholone compared with placebo would be associated with an SD of change between 2.0 and 2.5 kg. We conservatively estimated that the common SDs could be in the order of 2.5-3.0. With a sample size of 20-24 in the combined oxymetholone group and 10-12 subjects in the placebo group, the statistical power (1-beta ) was 0.80 to 0.90 to detect differences at the P < 0.05 level when the average change in total LBM by DEXA between the active treatment group and placebo was >= 3 kg.

Data were entered into Excel spreadsheets, and 100% of the entries were quality checked. Results were analyzed using the Statistical Package for Social Sciences (SPSS) version 10.0 software (SPSS, Chicago, IL). Baseline characteristics and change from baseline at study week 12 were compared among the groups by one-way analysis of variance (ANOVA). Bonferroni post hoc pairwise comparisons were made in the case of significant F-scores. Within-group changes were evaluated using paired t-tests. Variables whose distributions differed significantly from normal were analyzed using the nonparametric Kruskal-Wallis test. chi 2 Tests were used for categorical variables. A bidirectional alpha -level of significance was set at P = 0.05 for all measures. Summary statistics are reported in the tables and text as means ± 1 SD.


    RESULTS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Subjects

Thirty-three subjects were enrolled and randomized to the three treatment arms. One subject elected not to participate after providing informed consent but received no study therapy. A second subject missed a majority of doses during the last 6 wk of study therapy and was not included in the analysis; all other subjects were adherent (97 ± 5.9%) based on pill counts. The remaining 31 men completed all phases of the study. The three study groups were not significantly different in their baseline characteristics, including age, weight, BMI, blood counts, chemistries, PSA, total and free testosterone, and fasting serum lipids (Table 1). The total daily energy, protein and macronutrient intake also did not differ significantly among the three treatment groups. Although BMI appeared greater in the 50-mg group, there was no relation by Spearman correlation analyses (P values of 0.22-0.90) between baseline BMI and changes in body composition or strength during the study (data not shown).

                              
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Table 1.   Baseline characteristics of the study population

Body Composition Changes

Lean body mass. After 12 wk of treatment, total body weight changed little (-0.2 ± 1.1, 0.9 ± 2.0, and 1.5 ± 2.5 kg) in the placebo, 50 mg/day, and 100 mg/day groups, respectively, without significant within- or between-group changes. Total LBM increased significantly (P < 0.001) within the 50 mg/day and 100 mg/day groups (3.3 ± 1.2 and 4.2 ± 2.4 kg, respectively), and these increases in LBM in the two oxymetholone groups were each significantly (P < 0.001) different from the change (0.0 ± 0.6 kg) in the placebo group (Fig. 1).


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Fig. 1.   Changes in body composition are shown for the groups receiving placebo (filled bars), 50 mg of oxymetholone per day (open bars), and 100 mg per day (gray bars). Numbers above the bars represent the mean absolute changes and the error bars are ± 1 SE. For total lean body mass (LBM) and total fat, differences among the 3 groups were significant (P < 0.0001, one-way ANOVA). * Significant differences from placebo, P <=  0.001.

Fat mass. Although there was no change in total fat mass in the group that received placebo for 12 wk (0.0 ± 1.0 kg), total fat mass decreased significantly (P < 0.001) in the 50 mg/day and 100 mg/day (P <=  0.001) groups (-2.6 ± 1.2 and -2.5 ± 1.6 kg, respectively; Fig. 1). The absolute changes in trunk fat for the placebo, 50 mg/day, and 100 mg/day groups (0.2 ± 0.4, -1.7 ± 1.0, and -2.2 ± 0.9 kg, respectively) were significantly different from baseline only in the two oxymetholone treatment groups (P = 0.018 and P = 0.005). These changes in trunk and total fat mass were similar in the two active treatment groups (P = 0.91 and P = 0.99), indicating an absence of a dose-related response to the change in fat mass.

Appendicular body composition. The change in lower extremity lean tissue (primarily muscle) by DEXA was not significant for the three groups (0.1 ± 0.5, -0.2 ± 3.0, 1.0 ± 1.3 kg) after 12 wk of treatment (P = 0.54 by one-way ANOVA). However, upper-extremity LBM increased significantly and similarly in the 50 mg/day (0.7 ± 0.4 kg, P = 0.017) and 100 mg/day (0.7 ± 0.2 kg, P = 0.002; Fig. 2) groups. These changes were significantly different (P = 0.005) from those observed in the placebo group (0.0 ± 0.2 kg).


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Fig. 2.   Changes in regional composition (n = 16) are shown for the placebo, 50 mg/day, and 100 mg/day groups. A: nos. above bars represent mean absolute changes for trunk fat by dual-energy X-ray absorptiometry (DEXA). B: bars represent mean absolute changes (kg) for upper-extremity LBM (right arm plus left arm) by DEXA. C: muscle cross-sectional area of total proximal (gray bars) and posterior (filled bars) thigh muscles by magnetic resonance imaging. Error bars are ± 1 SE. * Significant difference from placebo, P <=  0.005. See text for other statistical analyses.

The MRI assessment of the proximal total thigh musculature showed a near-significant increase (24.5 ± 31.0 cm2, P = 0.056 by one-way ANOVA) in CSA for the 100 mg/day group compared with the placebo and 50 mg/day groups, for which there were no appreciable changes (-0.8 ± 6.1cm2, -1.6 ± 4.1 cm2, respectively; Fig. 2). Most of the putative change in leg muscle CSA was due to change in the posterior thigh muscles (-0.6 ± 3.2, -0.2 ± 2.8, 16.1 ± 19.5 cm2; P = 0.052 by one-way ANOVA).

Changes in Maximal Voluntary Strength

Chest press 1-RM strength increased significantly by 8.2 ± 9.2% (P = 0.04) in the 50 mg/day group and by 13.9 ± 8.1% (P = 0.002) in the 100 mg/day group (Fig. 3), resulting in a significant (P = 0.001) difference among the groups. Both the 50 mg/day and the 100 mg/day groups demonstrated significant increases compared with the placebo group (-0.8 ± 4.3%). Although the change was greater in the 100 mg/day group than in the 50 mg/day group, the difference was not statistically significant between these two groups. Similarly, the relative change in maximal lat pull-down strength differed significantly (P = 0.034) among the groups, due primarily to change in the 100 mg/day group (Fig. 3). In fact, lat pull-down strength increased significantly 18.4 ± 21.0% (P = 0.024) in the 100 mg/day group, whereas the 50 mg/day and placebo groups showed a nonsignificant 8.8 ± 15.1% increase (P = 0.15) and -0.6 ± 8.3 decrease (P = 0.42), respectively.


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Fig. 3.   Relative (%) changes in strength are shown for the groups receiving placebo (filled bars), 50 mg/day oxymetholone (open bars), and 100 mg/day oxymetholone (gray bars). Nos. above bars represent relative change (%) from baseline to week 12 for the 1-repetition maximum tests of strength. Error bars represent ± 1 SE from the mean. * Significant difference from placebo, P < 0.05; dagger significant difference from placebo by Wilcoxon test, P < 0.02. See text for additional statistical analyses.

Furthermore, there was a high correlation between change in upper extremity LBM with chest press and lat pull-down (r = 0.88 and r = 0.75, P < 0.001 and P = 0.001, respectively).

The percent increase in leg press strength was not significant in any of the three treatment groups (3.9-12.0%). However, there was a trend for change among the groups (P = 0.09 by one-way ANOVA); and the absolute increase of 174 ± 272 N in the 100 mg/day group from baseline to week 12 (Fig. 3) did not quite reach significance (P = 0.07 by paired t-test).

Changes in Hormone Levels

Serum LH decreased by 6.0 ± 4.1 and 5.6 ± 9.7 U/l in 50 mg/day and 100 mg/day treatment groups, respectively, which were both significantly different from the changes observed in the placebo group (Table 2). Likewise, serum SHBG concentrations decreased by -54.9 ± 25.8 and -45 ± 16.2 nmol/l in the 50- and 100-mg treatment groups, and these changes were significantly different from baseline (P < 0.001). Fasting insulin concentrations and derived indexes of insulin sensitivity using either the HOMA-IR model or the QUICKI method did not change significantly within treatment groups, nor were there differences between these groups (Table 2).

                              
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Table 2.   Change in safety measures after 12 wk of study therapy

Safety Evaluation

Table 2 shows that a significantly greater increase in mean ALT and aspartate aminotransferase (AST) occurred in the group that received the 100-mg dose of oxymetholone than in the other two groups. However, the ALT did not exceed 1.5 times the ULN except in two subjects (1.6 and 3.1 × ULN) in this group. Subjects who developed elevated ALT and AST remained asymptomatic and did not develop hepatomegaly, and their bilirubin and alkaline phosphatase levels remained normal. The subject with the highest increase in ALT admitted to drinking three to four glasses of wine per day during the period shortly before the tests were drawn. He was advised to discontinue alcohol, and his liver tests 1 wk later were normal. A small but statistically significant decrease in serum albumin occurred in the two oxymetholone treatment groups.

Changes in total cholesterol, LDL-cholesterol, and fasting triglycerides with study therapy did not differ among the three groups (Table 2). In addition, there were no significant within-group changes for these three lipids (P > 0.05 for each). However, decreases in plasma HDL-cholesterol concentrations (-19 ± 9 and -23 ± 18 mg/dl) were significantly greater (P = 0.05) than for placebo (-4.4 ± 11.3 mg/dl). There was no difference in the change in HDL between the two groups who received oxymetholone.

Changes in hematocrit and PSA did not differ among the three treatment groups (Table 2). All subjects had digital rectal examinations before and at the completion of study therapy, and none showed important change in their prostate glands (e.g., new nodules or unusual firmness).


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

The results of our study demonstrate that treatment with oxymetholone for 12 wk significantly augmented total LBM and maximum voluntary strength in older men, a segment of the population that is at risk for sarcopenia (4, 17, 18, 35). Indeed, with 50 and 100 mg/day of oxymetholone, total LBM increased by 3.3 ± 1.2 and 4.2 ± 2.4 kg, respectively. These effects are of a magnitude similar to that achieved with 125 and 300 mg of testosterone enanthate (2.9 ± 0.8 and 5.5 ± 0.7 kg, respectively) when administered by intramuscular injection weekly for 20 wk to young healthy men (7). Although the anabolic potency and pharmacokinetics of testosterone enanthate and oxymetholone likely differ, our results suggest that important enhancements in lean tissue can be achieved with androgen administration in older persons as in younger men.

Although it is possible that increases in LBM as measured by DEXA were related to water retention caused by the androgen therapy, the sizeable gains in muscle strength as measured by the 1-RM method in the 50 and 100 mg/day groups (8.2-18.4%) suggest that the increases in LBM were likely due to accretion of myofibrillar protein as well as total LBM, since strength is closely related to muscle size (34). Moreover, members of our group have reported that changes in appendicular LBM by DEXA are quantitatively related to changes in skeletal muscle strength in response to anabolic stimuli (45). Indeed, in the present study, we were able to corroborate this relationship by demonstrating that the significant increases in upper-body lean tissue by appendicular DEXA scanning were highly correlated with changes in upper-body strength as assessed by chest press and lat pull-down. Furthermore, changes in maximal voluntary muscle strength for the upper-body exercises showed a dose-related response.

In contrast, there were nonsignificant gains across the three treatment groups for lower extremity strength (3.9-12.0%), consistent with the lack of a significant increase in lower-extremity LBM by DEXA scanning. However, there was a near-significant difference (P = 0.052) between the groups for change in CSA of the thigh muscles by MRI, suggesting that study therapy may have positively affected lower-extremity muscle. It is possible that strength tests of multiple, large-muscle groups such as those used with the leg press exercise are less sensitive to modest change in muscle mass, and the study may not have had sufficient power to detect small but significant gains in the lower extremities. We speculate that the large leg muscles are routinely used more frequently for load bearing (e.g., walking, rising from a chair) compared with upper-extremity muscles in older adults. Small but significant gains in lower-body strength and muscle mass may be less demonstrable than for muscles of the upper body, which may be used less for high-volume work and more prone to sarcopenia in older persons. Additionally, muscles of the upper extremities, compared with muscles of the lower extremities, have greater proportions of fast-twitch, type II fibers (31, 43), which may be preferentially lost with aging (30). Furthermore, a longitudinal study in older men showed that type I fibers were lost primarily in the vastus lateralis of the leg (17), leading us to speculate that there might be greater loss in type II fibers in the arms with aging. Thus the response to anabolic stimuli may be more readily demonstrable in the upper extremities of this population.

There were also significant but similar within-group decreases in total body fat of 2.6 ± 1.2 and 2.5 ± 1.6 kg in the 50 and 100 mg/day groups, respectively. Of importance, a major portion of the improvement in adiposity involved decrements in trunk fat (1.7 ± 1.0 and 2.2 ± 0.9 kg in the two respective active treatment groups). A significant reduction in trunk fat could be expected to favorably affect risk factors for cardiovascular disease (32, 33). Although we would expect the reduction in abdominal fat to be reflected by improved insulin sensitivity, our indirect measures (HOMA-IR and QUICKI) may not have been sensitive enough. It is also possible that there were too few subjects in each group to detect small but meaningful changes.

There are theoretical reasons to have concern that androgen excess may result in or be associated with insulin resistance, although this relationship has been substantiated only in women with polycystic ovary syndrome (10, 11). We did not directly measure insulin sensitivity by either the hyperinsulinemic euglycemic clamp or frequently sampled intravenous glucose tolerance tests. However, indirect measures of insulin sensitivity (fasting insulin, HOMA-IR, QUICKI) did not show evidence of insulin resistance.

Liver transaminases (AST and ALT) increased only in the 100 mg/day treatment group. However, these changes were modest, and subjects remained asymptomatic and had no hepatic enlargement or evidence of cholestasis. There were no changes in total or LDL-cholesterol or fasting triglycerides, but HDL-cholesterol decreased significantly in the two oxymetholone groups (-19 ± 9 and -23 ± 18 mg/dl). Androgen effects on plasma lipids depend on the dose, route of administration, and type of androgen used (aromatizable or not). Thus nonaromatizable, orally administered androgens such as oxymetholone are expected to produce greater reductions in plasma HDL cholesterol than aromatizable testosterone (16, 54). Hematocrit did not increase significantly in the study groups, but this lack of change may have been related to phlebotomy for the collection of multiple specimens.

Observations that eunuchs do not develop cancer of the prostate (59) and that androgen ablation is an effective therapy for treatment of prostatic carcinoma (51) have led to concern that supplemental androgen therapy could increase the risk for enlargement of the prostate or even unmask carcinoma (52). In our study, there was no change in the texture of the prostate gland by digital examination or increase in serum PSA with treatment. This observation is consistent with the findings of Snyder et al. (50), who did not find significant differences in PSA levels after 3 yr between placebo and testosterone-treated older men with initially low or low normal testosterone levels.

Oxymetholone administration was associated with decreases in serum LH and SHBG concentrations. Therefore, at the doses of oxymetholone that are used for anabolic applications, this compound has significant androgenic activity at the hypothalamic-pituitary level. Unsubstantiated claims notwithstanding, it remains to be seen whether the androgenic and anabolic properties of androgens can be dissociated (8, 60).

Several limitations may have influenced the findings of this study. First, the small sample size of fewer than a dozen subjects per group may have limited the ability to detect small but important changes in variables such as lower-extremity LBM and CSA of thigh musculature. Similarly, it is possible that the differences observed for changes in total LBM and strength might have been significant between the treatment groups with larger sample sizes. The latter would have provided further support for our supposition of a dose-dependent response with oxymetholone. Second, our population represented older adult men, whom we characterized as being at risk for age-related sarcopenia on the basis of reports showing loss of muscle mass and strength with aging (4, 17, 18, 35). However, subjects were not recruited for weight loss, frailty, or overt hypogonadism per se, since we have shown that younger men with normal testosterone concentrations can achieve appreciable increases in muscle mass and strength after androgen supplementation (5, 7, 44). Furthermore, there is evidence that myofibrillar protein synthesis in older persons may be significantly augmented to levels comparable to those achieved in younger persons in response to a potent anabolic stimulus (21). Finally, because oxymetholone is a 17- methyl-substituted analog resulting in a high first-pass effect in the liver, additional safety data in older subjects should be obtained before this agent is used for treatment of sarcopenia. Regardless, the important observation from this study is that measures of muscle mass and maximal voluntary strength can be significantly improved in older persons with supplemental androgen therapy.

In summary, results of this study indicate that, in older men, supplementation with a brief course of androgen therapy can significantly increase lean tissue and maximal voluntary skeletal muscle strength. These translational findings are consistent with earlier studies showing that androgens increase synthesis of myofibrillar proteins and further document the plasticity of muscle in older people. The results also suggest that these changes were quantitatively related to the dose of oxymetholone. Of importance, there were also significant decreases in trunk fat in the active treatment groups consistent with findings in middle-aged men with abdominal obesity and relative hypogonadism. The study leaves a number of issues unresolved, including the optimal formulation of androgen for supplementation in this age group, the benefits and risks of longer periods of therapy, the durability of outcomes associated with intermittent therapy, the question of whether measures of visceral adipose tissue and markers of atherosclerosis are improved, and the question of whether similar beneficial effects can be achieved in older women.


    ACKNOWLEDGEMENTS

We thank the subjects who committed substantial time and efforts to make this a successful study, and Tom Wright for excellent technical assistance in performing the insulin, glucose, and lipid assays.


    FOOTNOTES

This investigator-initiated study was supported primarily by funding from the National Center for Research Resources General Clinical Research Center (MOI RR-430) and a grant-in-aid from Unimed Pharmaceuticals. Additional support was provided by National Institutes of Health Grants 1RO1 AG-14369-01, 1RO1 DK-59627-01, 2RO1 DK-49296-02A, and 1RO1 DK-49308-04, the Clinical Trials Unit Grant U01-DK-54047, RCMI Clinical Research Infrastructure Initiative (P20 RR-11145), and Research Center for Minority Institutions Grants G12 RR-03026 and U54 RR-14616.

Address for reprint requests and other correspondence: F. R. Sattler, Rand Schrader Clinic, Rm. 351, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033.

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

September 24, 2002;10.1152/ajpendo.00363.2002

Received 15 August 2002; accepted in final form 18 September 2002.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Bassey, EJ, Fiatarone MA, O'Neill EF, Kelly M, Evans WJ, and Lipsitz LA. Leg extensor power and functional performance in very old men and women. Clin Sci (Colch) 82: 321-327, 1992[ISI][Medline].

3.   Baumgartner, RN, Koehler KM, Gallagher D, Romero L, Heymsfield SB, Ross RR, Garry PJ, and Lindeman RD. Epidemiology of sarcopenia among the elderly in New Mexico. Am J Epidemiol 147: 755-763, 1998[Abstract].

4.   Baumgartner, RN, Waters DL, Gallagher D, Morley JE, and Garry PJ. Predictors of skeletal muscle mass in elderly men and women. Mech Ageing Dev 107: 123-136, 1999[ISI][Medline].

5.   Bhasin, S, Storer TW, Berman N, Callegari C, Clevenger B, Phillips J, Bunnell TJ, Tricker R, Shirazi A, and Casaburi R. The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men. N Engl J Med 335: 1-7, 1996[Abstract/Free Full Text].

6.   Bhasin, S, Storer TW, Berman N, Yarasheski KE, Clevenger B, Phillips J, Lee WP, Bunnell TJ, and Casaburi R. Testosterone replacement increases fat-free mass and muscle size in hypogonadal men. J Clin Endocrinol Metab 82: 407-413, 1997[Abstract/Free Full Text].

7.   Bhasin, S, Woodhouse L, Casaburi R, Singh AB, Bhasin D, Berman N, Chen X, Yarasheski KE, Magliano L, Dzekov C, Dzekov J, Bross R, Phillips J, Sinha-Hikim I, Shen R, and Storer TW. Testosterone dose-response relationships in healthy young men. Am J Physiol Endocrinol Metab 281: E1172-E1181, 2001[Abstract/Free Full Text].

8.   Bhasin, S, Woodhouse L, and Storer TW. Proof of the effect of testosterone on skeletal muscle. J Endocrinol 170: 27-38, 2001[Abstract/Free Full Text].

9.   Brodsky, IG, Balagopal P, and Nair KS. Effects of testosterone replacement on muscle mass and muscle protein synthesis in hypogonadal men---a clinical research center study. J Clin Endocrinol Metab 81: 3469-3475, 1996[Abstract].

10.   Carmina, E, Koyama T, Chang L, Stanczyk FZ, and Lobo RA. Does ethnicity influence the prevalence of adrenal hyperandrogenism and insulin resistance in polycystic ovary syndrome? Am J Obstet Gynecol 167: 1807-1812, 1992[ISI][Medline].

11.   Dunaif, A. Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. Endocr Rev 18: 774-800, 1997[Abstract/Free Full Text].

12.   Dutta, C, Hadley E, and Lexell J. Sarcopenia and physical performance in old age: overview. Muscle Nerve Suppl 5: S5-S9, 1997[Medline].

13.   Ferrando, AA, Sheffield-Moore M, Yeckel CW, Gilkison C, Jiang J, Achacosa A, Lieberman SA, Tipton K, Wolfe RR, and Urban RJ. Testosterone administration to older men improves muscle function: molecular and physiological mechanisms. Am J Physiol Endocrinol Metab 282: E601-E607, 2002[Abstract/Free Full Text].

14.   Fleck, S, and Kraemer WJ. Designing resistance training programs. In: Human Kinetics (2nd ed.). Champaign, IL: Human Kinetics, 1997, p. 4, 98-100.

15.   Friedewald, WT, Levy RI, and Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 18: 499-502, 1972[Abstract/Free Full Text].

16.   Friedl, KE, Hannan CJ, Jr, Jones RE, and Plymate SR. High-density lipoprotein cholesterol is not decreased if an aromatizable androgen is administered. Metabolism 39: 69-74, 1990[ISI][Medline].

17.   Frontera, WR, Hughes VA, Fielding RA, Fiatarone MA, Evans WJ, and Roubenoff R. Aging of skeletal muscle: a 12-yr longitudinal study. J Appl Physiol 88: 1321-1326, 2000[Abstract/Free Full Text].

18.   Gallagher, D, Visser M, De Meersman RE, Sepulveda D, Baumgartner RN, Pierson RN, Harris T, and Heymsfield SB. Appendicular skeletal muscle mass: effects of age, gender, and ethnicity. J Appl Physiol 83: 229-239, 1997[Abstract/Free Full Text].

19.   Grinspoon, S, Corcoran C, Miller K, Biller BM, Askari H, Wang E, Hubbard J, Anderson EJ, Basgoz N, Heller HM, and Klibanski A. Body composition and endocrine function in women with acquired immunodeficiency syndrome wasting. J Clin Endocrinol Metab 82: 1332-1337, 1997[Abstract/Free Full Text].

20.   Harman, SM, Metter EJ, Tobin JD, Pearson J, and Blackman MR. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging. J Clin Endocrinol Metab 86: 724-731, 2001[Abstract/Free Full Text].

21.   Hasten, DL, Pak-Loduca J, Obert KA, and Yarasheski KE. Resistance exercise acutely increases MHC and mixed muscle protein synthesis rates in 78-84 and 23-32 yr olds. Am J Physiol Endocrinol Metab 278: E620-E626, 2000[Abstract/Free Full Text].

22.   Holloszy, JO. Workshop on sarcopenia: muscle atrophy in old age. J Gerontol Biol Med Sci 50: 1-161, 1995[ISI].

23.   Katz, A, Nambi SS, Mather K, Baron AD, Follmann DA, Sullivan G, and Quon MJ. Quantitative insulin sensitivity check index: a simple, accurate method for assessing insulin sensitivity in humans. J Clin Endocrinol Metab 85: 2402-2410, 2000[Abstract/Free Full Text].

24.   Katznelson, L, Finkelstein JS, Schoenfeld DA, Rosenthal DI, Anderson EJ, and Klibanski A. Increase in bone density and lean body mass during testosterone administration in men with acquired hypogonadism. J Clin Endocrinol Metab 81: 4358-4365, 1996[Abstract].

25.   Kenny, AM, Prestwood KM, Gruman CA, Marcello KM, and Raisz LG. Effects of transdermal testosterone on bone and muscle in older men with low bioavailable testosterone levels. J Gerontol A Biol Sci Med Sci 56: M266-M272, 2001[Abstract/Free Full Text].

26.   Kenny, AM, Prestwood KM, and Raisz LG. Short-term effects of intramuscular and transdermal testosterone on bone turnover, prostate symptoms, cholesterol, and hematocrit in men over age 70 with low testosterone levels. Endocr Res 26: 153-168, 2000[ISI][Medline].

27.   Kotler, DP, Burastero S, Wang J, and Pierson RN, Jr. Prediction of body cell mass, fat-free mass, and total body water with bioelectrical impedance analysis: effects of race, sex, and disease. Am J Clin Nutr 64: 489S-497S, 1996[Abstract].

28.   Laakso, M. How good a marker is insulin level for insulin resistance? Am J Epidemiol 137: 959-965, 1993[Abstract].

29.   Lansang, MC, Williams GH, and Carroll JS. Correlation between the glucose clamp technique and the homeostasis model assessment in hypertension. Am J Hypertens 14: 51-53, 2001[ISI][Medline].

30.   Lexell, J. Human aging, muscle mass, and fiber type composition. J Gerontol A Biol Sci Med Sci 50: 11-16, 1995[ISI][Medline].

31.   MacDougall, JD, Elder GC, Sale DG, Moroz JR, and Sutton JR. Effects of strength training and immobilization on human muscle fibres. Eur J Appl Physiol Occup Physiol 43: 25-34, 1980[ISI][Medline].

32.   Marin, P, Holmang S, Jonsson L, Sjostrom L, Kvist H, Holm G, Lindstedt G, and Bjorntorp P. The effects of testosterone treatment on body composition and metabolism in middle-aged obese men. Int J Obes Relat Metab Disord 16: 991-997, 1992[Medline].

33.   Marin, P, Oden B, and Bjorntorp P. Assimilation and mobilization of triglycerides in subcutaneous abdominal and femoral adipose tissue in vivo in men: effects of androgens. J Clin Endocrinol Metab 80: 239-243, 1995[Abstract].

34.   Maughan, RJ, Watson JS, and Weir J. Strength and cross-sectional area of human skeletal muscle. J Physiol 338: 37-49, 1983[Abstract].

35.   Melton, LJ, III, Khosla S, Crowson CS, O'Connor MK, O'Fallon WM, and Riggs BL. Epidemiology of sarcopenia. J Am Geriatr Soc 48: 625-630, 2000[ISI][Medline].

36.   Morley, JE, Kaiser FE, Perry HM, III, Patrick P, Morley PM, Stauber PM, Vellas B, Baumgartner RN, and Garry PJ. Longitudinal changes in testosterone, luteinizing hormone, and follicle-stimulating hormone in healthy older men. Metabolism 46: 410-413, 1997[ISI][Medline].

37.   Morley, JE, Perry HM, III, Kaiser FE, Kraenzle D, Jensen J, Houston K, Mattammal M, and Perry HM, Jr. Effects of testosterone replacement therapy in old hypogonadal males: a preliminary study. J Am Geriatr Soc 41: 149-152, 1993[ISI][Medline].

38.   Narici, MV, Hoppeler H, Kayser B, Landoni L, Claassen H, Gavardi C, Conti M, and Cerretelli P. Human quadriceps cross-sectional area, torque and neural activation during 6 months strength training. Acta Physiol Scand 157: 175-186, 1996[ISI][Medline].

39.   Penninx, BW, Guralnik JM, Ferrucci L, Simonsick EM, Deeg DJ, and Wallace RB. Depressive symptoms and physical decline in community-dwelling older persons. JAMA 279: 1720-1726, 1998[Abstract/Free Full Text].

40.   Perry, HM, III, Miller DK, Patrick P, and Morley JE. Testosterone and leptin in older African-American men: relationship to age, strength, function, and season. Metabolism 49: 1085-1091, 2000[ISI][Medline].

41.   Rantanen, T, Penninx BW, Masaki K, Lintunen T, Foley D, and Guralnik JM. Depressed mood and body mass index as predictors of muscle strength decline in old men. J Am Geriatr Soc 48: 613-617, 2000[ISI][Medline].

42.   Reaven, GM. Syndrome X: 6 years later. J Intern Med Suppl 736: 13-22, 1994[Medline].

43.   Roy, RR, Meadows ID, Baldwin KM, and Edgerton VR. Functional significance of compensatory overloaded rat fast muscle. J Appl Physiol 52: 473-478, 1982[Abstract/Free Full Text].

44.   Sattler, FR, Jaque SV, and Schroeder ET. Effects of pharmacologic doses of nandrolone decanoate and progressive resistance training in immunodeficient patients infected with HIV. J Clin Endocrinol Metab 84: 1268-1276, 1999[Abstract/Free Full Text].

45.   Schroeder, E, Jaque S, Hawkins S, Olson C, Wiswell R, and Sattler F. Regional DXA and MRI in assessment of muscle adaptation to anabolic stimuli. Clin Exercise Physiol 3: 199-206, 2001.

46.   Sih, R, Morley JE, Kaiser FE, Perry HM, III, Patrick P, and Ross C. Testosterone replacement in older hypogonadal men: a 12-month randomized controlled trial. J Clin Endocrinol Metab 82: 1661-1667, 1997[Abstract/Free Full Text].

47.   Singh, AB, Norris K, Modi N, Sinha-Hikim I, Shen R, Davidson T, and Bhasin S. Pharmacokinetics of a transdermal testosterone system in men with end stage renal disease receiving maintenance hemodialysis and healthy hypogonadal men. J Clin Endocrinol Metab 86: 2437-2445, 2001[Abstract/Free Full Text].

48.   Sinha-Hikim, I, Arver S, Beall G, Shen R, Guerrero M, Sattler F, Shikuma C, Nelson JC, Landgren BM, Mazer NA, and Bhasin S. The use of a sensitive equilibrium dialysis method for the measurement of free testosterone levels in healthy, cycling women and in human immunodeficiency virus-infected women. J Clin Endocrinol Metab 83: 1312-1318, 1998[Abstract/Free Full Text].

49.   Snyder, PJ, Peachey H, Berlin JA, Hannoush P, Haddad G, Dlewati A, Santanna J, Loh L, Lenrow DA, Holmes JH, Kapoor SC, Atkinson LE, and Strom BL. Effects of testosterone replacement in hypogonadal men. J Clin Endocrinol Metab 85: 2670-2677, 2000[Abstract/Free Full Text].

50.   Snyder, PJ, Peachey H, Hannoush P, Berlin JA, Loh L, Lenrow DA, Holmes JH, Dlewati A, Santanna J, Rosen CJ, and Strom BL. Effect of testosterone treatment on body composition and muscle strength in men over 65 years of age. J Clin Endocrinol Metab 84: 2647-2653, 1999[Abstract/Free Full Text].

50a.   Swerdloff, RS, and Wang C. Androgens and aging in men. Exp Gerontol 28: 435-446, 1993[ISI][Medline].

51.   Taplin, ME, and Ho SM. Clinical review 134: the endocrinology of prostate cancer. J Clin Endocrinol Metab 86: 3467-3477, 2001[Free Full Text].

52.   Tenover, JS. Effects of testosterone supplementation in the aging male. J Clin Endocrinol Metab 75: 1092-1098, 1992[Abstract].

53.   Tenover, JS. Androgen replacement therapy to reverse and/or prevent age-associated sarcopenia in men. Baillieres Clin Endocrinol Metab 12: 419-425, 1998[ISI][Medline].

54.   Thompson, PD, Cullinane EM, Sady SP, Chenevert C, Saritelli AL, Sady MA, and Herbert PN. Contrasting effects of testosterone and stanozolol on serum lipoprotein levels. JAMA 261: 1165-1168, 1989[Abstract].

55.   Urban, RJ, Bodenburg YH, Gilkison C, Foxworth J, Coggan AR, Wolfe RR, and Ferrando A. Testosterone administration to elderly men increases skeletal muscle strength and protein synthesis. Am J Physiol Endocrinol Metab 269: E820-E826, 1995[Abstract/Free Full Text].

56.   Wang, C, Alexander G, Berman N, Salehian B, Davidson T, McDonald V, Steiner B, Hull L, Callegari C, and Swerdloff RS. Testosterone replacement therapy improves mood in hypogonadal men-a clinical research center study. J Clin Endocrinol Metab 81: 3578-3583, 1996[Abstract].

57.   Wang, C, Swedloff RS, Iranmanesh A, Dobs A, Snyder PJ, Cunningham G, Matsumoto AM, Weber T, and Berman N. Transdermal testosterone gel improves sexual function, mood, muscle strength, and body composition parameters in hypogonadal men. Testosterone Gel Study Group. J Clin Endocrinol Metab 85: 2839-2853, 2000[Abstract/Free Full Text].

58.   Warnick, GR, and Albers JJ. A comprehensive evaluation of the heparin-manganese precipitation procedure for estimating high density lipoprotein cholesterol. J Lipid Res 19: 65-76, 1978[Abstract/Free Full Text].

59.   Wilson, CM, and McPhaul MJ. A and B forms of the androgen receptor are present in human genital skin fibroblasts. Proc Natl Acad Sci USA 91: 1234-1238, 1994[Abstract].

60.   Wilson, JD. Androgen abuse by athletes. Endocr Rev 9: 181-199, 1988[ISI][Medline].


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