1 Departments of Obstetrics and Gynaecology, and 2 Clinical Chemistry, Oulu University Hospital, Oulu and 3 Department of Physiology, University of Turku, Turku, Finland
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Key words: adrenal glands/HCG/LH/ovary/steroids
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In the human, increased LH secretion occurs in polycystic ovarian syndrome (PCOS) and in infertility, often concomitant with adrenocortical dysfunction. In a study by Pabon et al. it was shown that human adrenals express the luteinizing hormone receptor (LHR) gene in zona fasciculata and reticularis (Pabon et al., 1996). There is also circumstantial evidence that LH may affect adrenal androgen secretion (Lacroix et al., 1999
, 2001). This is supported by studies showing decreased serum dehydroepiandrosterone sulphate (DHEAS) levels during GnRH agonist treatment in women with PCOS (Azziz et al., 1998
; Bayhan et al., 2000
; De Leo et al., 2000
). In addition, in a recent study on transgenic female mice with chronically elevated serum LH concentrations, infertility, and aberrant ovarian tumours, it was found that the adrenal glucocorticoid production was increased when compared with control mice (Kero et al., 2000
). The observation was explained by ectopic LH-induced LHR expression in the adrenal gland. In conclusion, LH may play a role in the regulation of physiological adrenal androgen secretion, as well as in some pathological conditions such as PCOS where hyperandrogenism is associated with chronically elevated levels of LH (Martikainen et al., 1996
; Morin-Papunen et al., 2000
). To explore the importance of adrenals in female androgen secretion, and especially the possible role of LH in its regulation, we stimulated women at reproductive age with HCG before and during GnRH agonist treatment. In addition, to exclude the contribution of the ovaries to the androgen pool, oophorectomized post-menopausal women were also studied.
![]() |
Materials and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
HCG test
In group 1, the initial HCG test was performed 26 days after a spontaneous menstrual bleeding. After the i.m. injection of 5000 IU HCG (Pregnyl® 5000IU; Organon, Oss, The Netherlands) between 0700 and 0900 h, fasting blood samples for 17-hydroxyprogesterone (17-OHP), androstenedione, testosterone, E2, DHEA, DHEAS and cortisol measurements were collected at 0, 24, 48, 72 and 96 h. Thereafter, GnRH agonist treatment (Enanton®, Depot 3, 75 mg; Laboratoires Cassenne Osnay, Cerny-Pentoise Cedex, France) was started on day 2123 of the menstrual cycle, and HCG test was repeated 3 weeks after the agonist injection. In group 2, the first HCG test was performed between 0700 and 0900 h any time during ERT and the test was repeated 4 weeks after cessation of ERT. The blood samples were collected as described above.
Assays
The serum concentration of testosterone was analysed by using an automated chemiluminescence system (CibaCorning ACS-180, Medfield, MA, USA). The serum concentrations of LH and FSH were analysed by fluoroimmunoassays (Wallac Inc. Ltd, Turku, Finland) and radioimmunoassays (RIA) were used for 17-OHP, androstenedione, DHEA, DHEAS (Diagnostic Products Corporation, Los Angeles, CA, USA), E2 and cortisol (Orion Diagnostica, Oulunsalo, Finland), following the instructions of the manufacturers. Areas under curve (AUC) for the 17-OHP, androstenedione, testosterone, E2, DHEA, DHEAS, cortisol responses were calculated by the trapezoidal method. The intra- and interassay coefficients of variation were 4.9 and 6.5% for LH, 3.8 and 4.3% for FSH, 5.0 and 5.4% for 17-OHP, 5.0 and 8.6% for androstenedione, 4.0 and 5.6% for testosterone, and 5.7 and 6.4% for E2, 6.5 and 7.9% for DHEA, 5.3 and 7.0% for DHEAS and 4.0 and 4.3% for cortisol.
Statistics
To compare the absolute maximal serum levels of the hormones to the basal levels, paired sample t-tests were used for normally distributed variables and Wilcoxon signed rank test was used for variables with skewed distribution. The same tests were also used for comparison of the AUC. The limit of statistical significance was set at P < 0.05.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
|
|
Testosterone
Serum concentrations of testosterone were increased by 20% at 2472 h after HCG and returned to the starting level at 96 h. GnRH agonist decreased the basal level of serum testosterone by 38%, and in contrast to the response pattern before GnRH agonist, testosterone increased after HCG up to 96 h (Figure 2 and Table III
).
|
DHEA, DHEAS, cortisol
The serum levels of cortisol, DHEA and DHEAS did not change after HCG or GnRH agonist (Table I).
Group 2 (post-menopausal women)
E2
The basal concentration of E2 decreased in oophorectomized women from 0.19 ± 0.04 to 0.03 ± 0.00 after cessation of ERT. The HCG test had no influence on E2 concentration (Tables II and III).
|
Group 1 compared with group 2
The effects of GnRH agonist treatment and oophorectomy on basal steroid concentrations are summarized in Table IV.
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In women aged 2139 years, HCG stimulated the serum concentrations of 17-OHP, androstenedione, testosterone and E2 significantly and the treatment with GnRH agonist decreased the responses, reflecting ovarian contribution to synthesis of these steroids. This was also supported by the observation that the basal concentrations were significantly lower in oophorectomized women (17-OHP 57%, androstenedione 46%, testosterone 25%), and HCG did not increase their serum levels. Although the basal serum concentrations of ovarian steroids, especially those of E2, decreased during GnRH agonist treatment, the relative response to HCG did not change markedly. This demonstrates that the immediate ovarian response to gonadotrophic stimulation persists during pituitary downregulation, and as well known, estrogen secretion is primarily of ovarian origin.
In contrast to the ovarian steroids, a single dose of HCG did not stimulate the secretion of steroids previously thought to be primarily of adrenal origin, i.e. DHEA, DHEAS and cortisol. Despite these in-vivo results, it has been previously reported that upon short-term stimulation, the incubation of guinea pig adrenal cells with HCG for 2 h stimulated cortisol and androstenedione secretion significantly, and that ACTH enhanced the responses (O'Connell et al., 1994). These observations indicate that HCG/LH could play a role in modulating adrenal steroidogenesis in-vitro conditions. This is also supported by occasional earlier observations; for example, during pregnancy, plasma and urinary free cortisol levels are increased even though ACTH levels are low, suggesting a possible role of HCG in the regulation of adrenal steroid secretion (Fotherby, 1984
). In fact this has been demonstrated in in-vitro studies on human fetal adrenal cells (Serón-Ferré et al., 1978
). Furthermore, during adrenarche, adrenal androgen production begins to increase and reaches adult levels without concomitant increase in ACTH (Apter et al., 1979
). The purity of HCG may have varied between studies, which could explain some of the differences between in-vivo and in-vitro experiments.
The time of exposure to LH/HCG may also be important. Women with chronic anovulation have been reported to have elevated levels of LH and DHEAS but normal levels of ACTH (Hoffman et al., 1984). Transgenic (TG) mice with constitutive high LH secretion provide a useful model for studying disorders with chronically elevated serum LH and adrenal androgen production (Kero et al., 2000
). TG female mice exhibiting chronically elevated serum LH levels have been shown to have increased corticosterone production. Furthermore, LHR mRNA expression was detected in the adrenal glands, and they responded to HCG stimulation with significant increase in corticosterone production, and the response was greater when HCG was combined with ACTH. Interestingly, oophorectomized TG animals had normal corticosterone levels, suggesting a possible role of gonadal factors directly or indirectly in the regulation of adrenal steroidogenesis. Similarly, in the present study, the post-menopausal oophorectomized subjects had high serum LH levels and decreased DHEA and DHEAS levels compared with women in group 1. However, because the serum levels of these steroids decrease with age (Orentreich et al., 1984
; Laughil and Barrett-Connor, 2000
), the contribution of oophorectomy alone cannot be confirmed.
The first HCG test in group 2 was performed during ERT, to avoid the chronic effect of high endogenous gonadotrophin levels and consequent possible down-regulation of LHR. However, since the gonadotrophin levels in post-menopausal women were also high during ERT it is possible that the study design was not optimal for prevention of the possible complete down-regulation of LHR. Alternatively, it is also possible that oophorectomy had eliminated some important ovarian factors, for instance estrogens, that would be required for maintaining adrenal LHR as suggested based on the observations in gonadectomized TG mice (Kero et al., 2000). In the same study, they implied that E2 could play a part in adrenal androgen production by up-regulating prolactin secretion. Since prolactin is an important up-regulator of LHR expression (Huhtaniemi and Catt, 1981
; Gåfvels et al., 1992
; Pakarinen et al., 1994
), this hormone could be the ovary-dependent factor that enhances the LH responsiveness of the adrenal gland. The role of estrogens is emphasized by studies showing that E2 enhances adrenal sensitivity to ACTH in women with PCOS (Ditkoff et al., 1995
; Carmina et al., 1999
), although in normal post-menopausal women this effect has not been observed (Slayden et al., 1998
).
In conclusion, it can be approximated that the ovarian contribution for the synthesis of 17-OHP, androstenedione and testosterone is 2530%, and that the adrenals are the primary source of cortisol, DHEA and DHEAS. Whether a long-term exposure to LH/HCG affects adrenal function remains to be studied.
![]() |
Acknowledgements |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
![]() |
Notes |
---|
Submitted on August 3, 2001; resubmitted on September 20, 2001
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Azziz, R., Rittmaster, R., Fox, L., Bradley, E. Jr, Potter, H. and Boots, L. (1998) Role of the ovary in the adrenal androgen excess of hyperandrogenic women. Fertil. Steril., 69, 851859.[ISI][Medline]
Bayhan, G., Bahceci, M., Demirkol, T., Ertem, M., Yalinkaya, A. and Erden, A. (2000) A comparative study of a gonadotropin-releasing hormone agonist and finasteride on idiopathic hirsutism. Clin. Exp. Obstet. Gynecol., 27, 203206.[Medline]
Carmina, E., Gonzales, F., Vidali, A., Stanczyk, F.Z., Ferin, M. and Lobo, R.A. (1999) The contribution of oestrogen and growth factors to increase adrenal androgen secretion in polycystic ovary syndrome. Hum. Reprod., 14, 307311.
De Leo, V., Fulghesu, A., la Marca, A., Morgante, G., Pasqui, L., Talluri, B., Torricelli, M. and Caruso, A. (2000) Hormonal and clinical effects of GnRH agonist alone, or in combination with a combined oral contraceptive or flutamide in women with severe hirsutism. Gynecol. Endocrinol., 14, 411416.[ISI][Medline]
Ditkoff, E.C., Fruzzetti, F., Chang, L., Stancyzk, F.Z. and Lobo, R.A. (1995) The impact of estrogen on adrenal androgen sensitivity and secretion in polycystic ovary syndrome. J. Clin. Endocrinol. Metab., 80, 603607.[Abstract]
Fotherby, K. (1984) Endocrinology of menstrual cycle and pregnancy. In Making, H.L. (ed.) Biochemistry of steroid hormones. Blackwell Scientific, Oxford. pp. 409440.
Gåfvels, M., Bjurulf, E. and Selstam, G. (1992) Prolactin stimulates the expression of luteinizing hormone/chorionic gonadotropin receptor messenger acid in the rat corpus luteum and rescues early pregnancy from bromocriptin-induced abortion. Biol. Reprod., 47, 534540.[Abstract]
Glasow, A., Breidert, M., Haidan, A., Anderegg, U., Kelly, P.A. and Bornstein, S.R. (1996) Functional aspects of the effect of prolactin (PRL) on adrenal steroidogenesis and distribution of the PRL receptor in the human adrenal gland. J. Clin. Endocrinol. Metab., 81, 31033111.[Abstract]
Hoffman, D.I., Klove, K. and Lobo, R.A. (1984) The prevalence and significance of elevated dehydroepianrdosterone sulfate levels in anovulatory women. Fertil. Steril., 42, 7681.[ISI][Medline]
Huhtaniemi, I.T. and Catt, K.J. (1981) Induction of maintenance of gonadotropin and lactogen receptors in hyprolactinemic rats. Endocrinology, 109, 483490.[Abstract]
Kero, J., Poutanen, M., Zhang, F-P., Rahman, N., McNicol, A.M., Nilson, J.H., Keri, R.A. and Huhtaniemi, I.T. (2000) Elevated luteinizing hormone induces expression of its receptor and promotes steroidogenesis in the adrenal cortex. J. Clin. Invest., 105, 633641.
Lacroix, A., Hamet, P. and Boutin, J-M. (1999) Leuprolide acetate therapy in luteinizing hormone-dependent Cushing's syndrome. N. Engl. J. Med., 18, 15771581.
Lacroix, A., N'Diaye N., Tremblay, J. and Hamet, P. (2001) Ectopic and abnormal hormone receptors in adrenal Cushing's syndrome. Endocr. Rev., 22, 75110.
Laughil, G.A. and Barrett-Connor, E. (2000) Sexual dimorphism in the influence of advanced aging on adrenal hormone levels: the Rancho Bernardo study. J. Clin. Endocrinol. Metab., 85, 35613568.
Martikainen, H., Salmela, P., Nuojua-Huttunen, S., Perälä, J., Leinonen, S., Knip, M. and Ruokonen, A. (1996) Adrenal steroidogenesis is related to insulin in hyperandrogenic women. Fertil. Steril., 66, 564570.[ISI][Medline]
McKenna, T.J. and Cunningham, S.K. (1991) The control of adrenal androgen secretion. J. Endocrinol., 129, 13.[ISI]
McKenna, T., Fearon, U., Clarke, D. and Cunningham, S.K. (1997) A critical review of the origin and control of adrenal androgens. Baillières Clin. Obstet. Gynaecol., 11, 229247.[ISI][Medline]
Mircescu, H., Jilwan, J., N'Diaye, N., Bourdeau, I., Tremblay, J., Hamet, P. and Lacroix, A. (2000) Are ectopic or abnormal membrane hormone receptors frequently present in adrenal Cushing's syndrome? J. Clin. Endocrinol. Metab., 85, 35313536.
Morin-Papunen, L., Vauhkonen, I., Koivunen, R., Ruokonen, A. and Tapanainen, J.S. (2000) Insulin sensitivity, insulin secretion, and metabolic and hormonal parameters in healthy women and women with polycystic ovarian syndrome. Hum. Reprod., 15, 12661274.
O'Connell, Y., McKenna, T. and Cunningham, S. (1994) The effect of prolactin, human chorionic gonadotropin, insulin and insulin-like growth factor 1 on adrenal steroidogenesis in isolated guinea-pig adrenal cells. J. Steroid Biochem. Molec. Biol., 48, 235240.[ISI][Medline]
Orentreich, N., Brind, J.L., Rizer, R.L. and Vogelman, J.H. (1984) Age changes and sex differences in serum dehydroepiandrosterone sulfate concentrations throughout adulthood. J. Clin. Endocrinol. Metab., 59, 551555.[Abstract]
Pabon, J.E., Li, X., Lei, Z., Sanfilippo, J.S., Yussman, M.A. and Rao, V. (1996) Novel presence of luteinizing hormone/chorionic gonadotropin receptors in human adrenal glands. J. Clin. Endocrinol. Metab., 81, 23972400.[Abstract]
Pakarinen, P., Niemimaa, T., Huhtaniemi, I.T. and Warren, D.W. (1994) Transcriptional and translational regulation of LH, prolactin and their testicular receptors by HCG and bromocriptine treatments in adult and neonatal rats. Mol. Cell Endocrinol., 101, 3747.[ISI][Medline]
Parker, L.N. (1991) Control of adrenal androgen secretion. Endocrinol. Metab. Clin. N. Amer., 20, 401421.[ISI][Medline]
Penhoat, A., Chatelain, P., Jaillard, C. and Saez, J.M. (1988) Characterization of insulin-like growth factor I and insulin receptors on cultured bovine adrenal fasciculate cells. Role of these peptides on adrenal cell function. Endocrinology, 122, 25182526.[Abstract]
Pillion, D.J., Arnold, P., Yang, M., Stockard, C.R. and Grizzle, W.E. (1989) Receptors for insulin and insulin-like growth factor-I in the human adrenal gland. Biochem. Biophys. Res. Commun., 165, 204211.[ISI][Medline]
Serón-Ferré, M., Lawrence, C.C. and Jaffe, R.B. (1978) Role of HCG in regulation of the fetal zone of the human fetal adrenal gland. J. Clin. Endocrinol. Metab., 46, 834837.[Abstract]
Slayden, S., Crabbe, L., Bae, S., Potter, H.D., Azziz, R. and Parker, C.R. Jr (1998) The effect of 17 beta-estradiol on adrenocortical sensitivity, responsiveness, and steroidogenesis in post-menopausal women. J. Clin. Endocrinol. Metab., 83, 519524.
accepted on November 9, 2001.