Involvement of thioredoxin in the regulation of growth hormone secretion in rat pituitary cell cultures

Ikue Hata1, Yosuke Shigematsu2, Yusei Ohshima1, Hirokazu Tsukahara1, Kazuo Fujisawa1, Masahiro Hiraoka1, Hajime Nakamura3, Hiroshi Masutani3, Junji Yodoi3, Fumikazu Kotsuji4, Masakatsu Sudo1, and Mitsufumi Mayumi1

Departments of 1 Pediatrics, 2 Basic Nursing, and 4 Gynecology, Fukui Medical University, Fukui 910-1193; and 3 Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan


    ABSTRACT
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ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

We report here an examination of the effect of thioredoxin (TRX) on the secretion of growth hormone (GH) from rat anterior pituitary cells in vitro. Treatment of rat pituitary cells with growth hormone-releasing factor (GRF), but not GH, led to a significant increase in intracellular TRX protein levels. GRF, recombinant human TRX (rhTRX), and a combination thereof were all shown to induce immediate GH secretion from pituitary cells, as evidenced by perifusion experiments. RhTRX, but not other reducing agents such as beta -mercaptoethanol and N-acetyl-L-cysteine, augmented GRF-stimulated and -unstimulated GH secretion from rat pituitary cells in a dose-dependent manner. RhTRX did not significantly affect the GH mRNA expression of pituitary cells stimulated in the presence or absence of GRF. In addition, rhTRX-augmented GH secretion was not significantly affected by the presence of cycloheximide. Collectively, these findings suggest that TRX is induced by stimulation with GRF and plays a regulatory role in GH secretion from rat anterior pituitary cells by enhancing the secretion of stored GH, rather than by the synthesis of GH.

redox; growth hormone-releasing factor; disulfide bonds


    INTRODUCTION
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ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

IT HAS RECENTLY BEEN SHOWN that reduction/oxidation (redox) reactions are intimately involved in the control of biological processes including the functional modulation of transcription factors (25, 32). In the case of the endocrine system, the cellular redox state appears to regulate the secretion and action of hormones. With regard to the hypothalamic-pituitary axis, a critical role for nitric oxide (NO), an endogenous redox modulator (34), in the regulation of growth hormone (GH) secretion has been proposed. We and others (7, 13) have recently reported that cultured rat pituitary cells tonically produce NO, which, in turn, blunts the growth hormone-releasing factor (GRF)-induced GH secretion through a guanosine 3',5'-cyclic monophosphate (cGMP)-independent mechanism.

An important constituent of the oxidant buffering system that controls the cellular redox state is thioredoxin (TRX), a 12-kDa protein with a redox-active disulfide/dithiol in the conserved active site sequence Cys-Gly-Pro-Cys (9, 25). This molecule has a variety of activities including serving as a hydrogen donor for various intracellular molecules (15, 24). Evidence has accumulated that suggests the presence of a control mechanism by the TRX system in certain endocrine systems (3, 8). For example, in the hypothalamic-pituitary-adrenal axis, TRX modulates cellular glucocorticoid responsiveness (6, 22). In the human ovary, adult T-cell leukemia-derived factor, the human form of TRX, exists and may participate in steroid hormone production (11). Recent immunohistological studies (28, 29) have demonstrated an intense level of staining for TRX in the pig anterior pituitary gland, supporting the contention that the TRX system may play a role in the regulation of GH secretion. However, to date, no data are available regarding the role of TRX in the GRF-GH axis.

In the present study, we report on an investigation of the effect of GRF on the synthesis of TRX in rat anterior pituitary cells and the regulatory role of TRX in GH secretion from these cells. Our findings present the first evidence that suggests that the TRX system, which is stimulated by GRF, acts as an enhancer of GH secretion in the rat anterior pituitary gland.


    MATERIALS AND METHODS
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ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Pituitary cell dispersion. Anterior pituitary glands were collected from male Sprague-Dawley rats, aged 6-8 wk (Clea Japan, Tokyo, Japan). For >= 3 days before decapitation, the animals were kept in our animal facilities at 24°C on a 12:12-h light-dark cycle and received food and water ad libitum. Primary pituitary cell cultures were prepared as described previously (12, 14), with some modifications. Briefly, rat anterior pituitaries were finely minced and incubated with 0.3% type I collagenase (Sigma Chemical, St. Louis, MO) and 0.0009% DNase (Sigma Chemical) in Hanks'-HEPES buffer containing 0.4% BSA at 37°C for 20-30 min. The pituitary suspension was triturated through pasteur pipettes at 5-min intervals during the incubation.

The dispersed cells were washed three times with DMEM (GIBCO-BRL, Life Technologies, Rockville, MD) containing 10% fetal bovine serum (referred to hereinafter as the culture medium), resuspended in the culture medium, and used for the primary culture. The yield of cells was 7-10 × 105 cells/pituitary, and the viability was ~90%, based on the trypan blue exclusion test. The experimental protocol was approved by the animal care committee of our university.

Western blot analysis of GRF- or GH-induced TRX production. Dispersed pituitary cells were cultured at 1.0-1.5 × 105 cells · ml-1 · well-1 in 24-well culture plates (Corning, New York, NY) for 4-5 days. The confluently grown cells were then reincubated with 1 ml of the fresh culture medium/well for 24 h in the presence of 10-7 M human GRF-(1-44) (GRF; Peptide Institute, Osaka, Japan) or 500 ng/ml rat GH (kindly provided by Dr. A. F. Parlow, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD) during the last 0, 6, 12, and 24 h of the culture periods. The TRX contents in the cells were then determined by Western blot analysis as described previously (31). Briefly, the cultured cells were washed three times with ice-cold PBS and then treated with a solubilizing buffer [0.5% octylphenoxyl polyethoxyethanol (Nonidet P-40), 10 mM Tris · HCl, 150 mM NaCl, 1 mM phenylmethylsulfonyl fluoride, 0.111 U/ml aprotinin, and 0.02% NaN3] on ice for 30 min. The resultant lysates were centrifuged at 10,000 g for 10 min, and the supernatants were used for SDS-PAGE. The concentrations of protein in the supernatants were determined by the modified Lowry method (Bio-Rad Laboratories, Hercules, CA). Equal amounts of proteins (8 or 10 µg) were applied to each lane. After electrophoresis, proteins were electrically transferred onto a nitrocellulose membrane (Millipore, Bedford, MA). The membrane was blocked with 10% skim milk and 2% BSA and then incubated with rabbit antiserum to murine TRX (1:2,000 dilution) at 4°C overnight, followed by horseradish peroxidase-linked goat anti-rabbit immunoglobulins (1:100 dilution, according to the manufacturer's instructions) (ENVISION+, Dako Japan, Kyoto, Japan). Detection of the antigen-antibody complex was performed by enhanced chemiluminescence (Amersham Pharmacia Biotech, Buckinghamshire, UK) according to the manufacturer's instructions. Quantification of TRX was performed by densitometric analysis with an imaging densitometer (NIH image).

Effect of TRX, other reducing agents, and cycloheximide on GH secretion. Perifusion experiments were performed as previously described (14), with minor modifications. Briefly, dispersed pituitary cells were cultured with preswollen Cytodex microcarriers type 3 (Amersham Pharmacia Biotech) in the culture medium at a ratio of 1.0 × 106 cells to 10 mg microcarriers in 3-cm siliconized glass dishes. After 4-5 days of culture, the cells were packed into Lucite columns with microcarriers and placed in a 37°C incubator. Three columns were perifused simultaneously with DMEM at 0.5 ml/min and stimulated with DMEM containing GRF (10-9 M) or rhTRX (100 µg/ml; Ajinomoto, Kawasaki, Japan) or both for a 5-min period at 90-min intervals. The column effluents were collected every 2 min by means of a fraction collector and stored at -80°C for measurement of GH concentrations.

Dispersed pituitary cells in the culture medium were also seeded at a concentration of 6.0 × 104 cells · 500 µl-1 · well-1 in 48-well culture plates (Becton-Dickinson, Franklin Lakes, NJ). After 4-5 days of culture, the confluently grown cells were rinsed twice with DMEM and incubated for another hour with 300 µl of DMEM containing various concentrations of rhTRX (0-100 µg/ml) and/or GRF (10-9 M). The effect of beta -mercaptoethanol and N-acetyl-L-cysteine at the concentrations of 1 and 10 µM was compared with that of 1 and 10 µM rhTRX in some experiments; 1 and 10 µM rhTRX are equivalent to 12 and 120 µg/ml. In certain experiments, pituitary cells were incubated with rhTRX and/or GRF in the presence of cycloheximide (200 µM; Sigma Chemical) to prevent de novo protein synthesis. The medium was then collected and stored at -80°C until assayed for GH concentrations.

Measurement of GH concentrations. The concentrations of GH of the medium were measured by RIA, which was done in duplicate with a kit that was kindly provided by Dr. A. F. Parlow. RhTRX and other reducing agents at the concentrations used had no effect on the measurement of GH by RIA (data not shown).

Northern blot analysis of GH mRNA. Dispersed pituitary cells were cultured at a density of 2.5-4.1 × 105 cells/well in 2 ml of the culture medium in 6-well culture plates (Becton-Dickinson). After 4-5 days, the confluently grown cells were rinsed twice with DMEM and incubated with 2 ml of DMEM containing rhTRX (100 µg/ml) and/or GRF (10-9 M) for additional 4 h. At the end of the incubation, cells were washed twice with ice-cold PBS. Total cellular RNA was extracted with RNA isolation reagent (Isogen, Nippon Gene, Tokyo, Japan). Three micrograms of RNA were separated on a 1% agarose gel in 0.02 M 3-(N-morpholino)propanesulfonic acid buffer and then transferred to a nylon membrane (Hybond N+, Amersham Pharmacia Biotech). Hybridizations were performed using the rat GH cDNA probe labeled with deoxy[alpha -32P]cytidine 5'-triphosphate, which was kindly provided by the Bioscience Research Institute of JCR Pharmaceuticals (Kobe, Japan). A final series of washes was carried out at 2× saline-sodium citrate (SSC) buffer/0.1% SDS at room temperature, and 0.1 × SSC/0.1% SDS at 47°C. Quantification of GH mRNA was performed by densitometric analysis with the use of the NIH image.

Statistical analysis. All data are presented as means ± SE. Statistical comparisons were performed by one-way analysis of variance (ANOVA), with the use of the Bonferroni-Dunn test, and by the Student's t-test for the effect of cycloheximide and the effect of rhTRX on GH mRNA. P values <0.05 were considered statistically significant.


    RESULTS
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INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

Effect of GRF on intracellular TRX concentration. The effect of GRF on intracellular TRX levels was first examined in rat pituitary cells. Because our preliminary experiments showed that the incubation of pituitary cells with GRF for 6 h was insufficient to induce significant increases in TRX levels (data not shown), we determined TRX levels after 12 and 24 h of incubation with GRF in the following experiments. As shown in Fig. 1, A and B, the cultured rat pituitary cells contained detectable amounts of TRX, and stimulation of the cells with GRF significantly increased the intracellular TRX protein levels. The mean TRX protein levels of cells stimulated with GRF during the last 12 and 24 h of the culture period were 2.6 and 2.3 times higher, respectively, than that observed in the controls cultured without GRF throughout the culture period (Fig. 1B). These results indicate that GRF caused an increase in TRX protein levels within 12 h. In contrast, the TRX protein levels were not altered by GH stimulation at any time examined (Fig. 1, C and D). These results suggest that the GRF-induced increase in TRX is not due to an indirect effect via GH.


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Fig. 1.   Effects of growth hormone-releasing factor (GRF) and growth hormone (GH) on intracellular thioredoxin (TRX) protein levels. Confluently grown rat anterior pituitary cells were incubated for an additional 24 h with 10-7 M GRF (A and B) or 500 ng/ml of GH (C and D) during the indicated time periods of the incubation. Zero indicates that the cells were incubated for 24 h in the absence of GRF or GH as a control. A and C: representative Western blot analysis, the results of which were confirmed by repeated experiments. B and D: intracellular TRX protein levels (means ± SE of 3 independent experiments) of cells stimulated with GRF (B) or GH (D) for the indicated hours. Data are expressed as percentages of the intensity of the control bands (time 0). *P < 0.05 vs. time 0.

Effect of TRX on GH secretion. The possibility that TRX influenced GH secretion from rat pituitary cells was then examined. In perifusion experiments, the GH secretion significantly increased immediately after stimulation with 10-9 M GRF, 100 µg/ml rhTRX, or both (Fig. 2). The GH secretion reached maximum within 5 min after the start of stimulation with each stimulus and decreased rapidly after the cessation of the 5-min stimulation. The maximum GH secretion generated by GRF plus rhTRX was higher than those by GRF or rhTRX alone but was not statistically significant. The stimulation was repeated 3 or 4 times after 90-min intervals in each experiment, and the results were nearly the same (data not shown). The cell viability at the end of the perifusion experiments was 90-93%, regardless of the stimuli (data not shown).


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Fig. 2.   GH secretion from cultured rat anterior pituitary cells in response to short-term treatment. Cultured cells, packed into columns, were perifused with the medium and exposed to GRF (10-9 M; open circle ), recombinant human (rh)TRX (100 µg/ml; black-triangle), or both () for 5 min. The concentrations of GH in the effluents, collected at 2-min intervals, were measured. Changes in GH secretion (means ± SE of quadruplicated determinants) are expressed as percentages of the basal GH concentration, which is the mean of 5 fractions just before stimulation. Results were confirmed by 3 independent experiments, and representative data are shown. There is no statistically significant difference among the peaks of GH secretion induced by the 3 different stimuli.

The dose response of rhTRX on GH secretion was then examined. Rat pituitary cells were stimulated for 1 h with different concentrations of rhTRX in the presence or absence of GRF. As shown in Fig. 3, rhTRX at concentrations of 1-100 µg/ml augmented GRF-stimulated and -unstimulated GH secretion from rat pituitary cells in dose-dependent manners, and the increase was significant when higher concentrations of rhTRX were used.


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Fig. 3.   TRX-induced GH secretion from cultured rat anterior pituitary cells. Confluently grown pituitary cells were incubated in culture wells for an additional 1 h with the indicated concentrations of rhTRX in the presence () or absence (open circle ) of 10-9 M of GRF. Data in A show the concentrations of GH (means ± SE of quadruplicate determinants) of the representative experiment. Increases in GH concentration (means ± SE of 5 independent experiments) stimulated with rhTRX in the presence and absence of GRF are shown in B and C, respectively, as the percentages of those cultured without rhTRX. *P < 0.05; **P < 0.01 vs. without TRX.

Effect of cycloheximide on GH secretion. Because the TRX-induced augmentation of GH secretion was observed immediately after stimulation with rhTRX (Figs. 2 and 3), it is likely that TRX shows its effect through the secretion of intracellularly stored GH but through an augmentation in the de novo synthesis of GH. To confirm this possibility, pituitary cells were stimulated with rhTRX in the presence of cycloheximide. As shown in Fig. 4, cycloheximide had no significant effect on the amounts of GH secreted by the cells treated with rhTRX and/or GRF.


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Fig. 4.   Effect of cycloheximide on GH secretion. Confluently grown pituitary cells were treated with 100 µg/ml rhTRX (A), or with 100 µg/ml rhTRX plus 10-9 M GRF (B) for 1 h in the presence or absence of 200 µM cycloheximide, as indicated. Changes in GH concentration (means ± SE of 4 independent experiments) are shown as percentages of those cultured without rhTRX and cycloheximide. n.s., Nonsignificant.

Effect of TRX on GH mRNA expression. As shown in Fig. 5, rhTRX had no effect on GH mRNA levels in rat pituitary cells cultured with or without GRF, even after 4 h. The data also suggest that rhTRX enhances the secretion of stored GH but not the de novo synthesis of GH.


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Fig. 5.   Effect of GRF and TRX on GH mRNA expression. Expression of GH mRNA of rat pituitary cells stimulated with rhTRX (100 µg/ml), GRF (10-9 M), or both for 4 h was determined by Northern blot analysis and densitometric analysis. The contents of GH mRNA were corrected according to those of beta -actin. A: representative autoradiograph; data were confirmed by repeated experiments. B: changes in GH mRNA levels (means ± SE of 3 independent experiments) are expressed as the percentages of those cultured without rhTRX or GRF.

Effects of other reducing agents on GH secretion. Although rhTRX significantly augmented GH secretion, beta -mercaptoethanol and N-acetyl-L-cysteine at concentrations of 1 and 10 µM had no significant effect on GH secretion (Fig. 6). The viability of cells was not changed regardless of the treatments (data not shown).


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Fig. 6.   Effects of reducing agents on GH secretion. Confluently grown rat pituitary cells were incubated for 1 h with or without beta -mercaptoethanol (open circle ), N-acetyl-L-cysteine () and rhTRX (black-triangle) at concentrations of 1 and 10 µM in the presence (A) or absence (B) of GRF (10-9 M). Changes in GH concentrations of medium are shown as percentages of those cultured without the reducing agents. Shown are means ± SE of 4 independent experiments, each of which is the mean of quadruplicated determinants. **P < 0.01 vs. without reducing agents.


    DISCUSSION
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ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

The physiological secretion of GH is generally thought to be regulated primarily by the two hypothalamic peptides GRF and somatostatin (5, 35), and redox modulation of disulfide bonds of hormones and receptors has been shown to influence GH secretion (4, 21, 36) as well as hormone-induced receptor activation (6, 8) and signal transduction (23). A redox-modulatory substance, NO, modulates the GRF-stimulated secretion of GH from rat pituitary cell cultures (13). TRX, another important redox-modulatory substance, has recently been identified in pig anterior pituitary gland by immunohistochemical analysis (28, 29). Immunoblotting analysis suggests that this is the case in calf and rat pituitary as well. This suggests that the TRX system is widely involved in the regulation of GH secretion from anterior pituitary gland. The data reported herein represent the first implication of the GRF-TRX-GH axis in rat pituitary gland.

The present findings show that stimulation with GRF increased TRX levels in rat anterior pituitary cells, and extrinsic rhTRX induced secretion of GH therefrom. Although the issue of whether GRF directly induces TRX production or indirectly induces it through induction/augmentation of other proteins is not clear, our results show that GH is not possibly the indirect inducer. The fact that TRX can be induced through a cAMP-dependent pathway (37), and that GRF is capable of activating a cAMP-dependent pathway in pituitary cells (1, 2, 4), suggests that GRF directly induces the synthesis of TRX protein in rat pituitary cells through a cAMP-dependent pathway.

Several possible explanations exist for the rhTRX-induced augmentation of GH secretion from rat pituitary cells, including the induction of de novo GH synthesis, augmentation of secretion of stored GH, or both. The fact that stimulation with rhTRX immediately elicited GH secretion (Fig. 2), that cycloheximide did not influence rhTRX-induced GH secretion (Fig. 4), and that rhTRX did not appear to upregulate GH mRNA expression (Fig. 5), suggests that rhTRX augments GH secretion by increasing the secretion of stored GH but not through the induction of the de novo synthesis of GH. GH is stored in pituitary secretory granules in high concentrations in the form of intermolecular disulfide-bonded oligomers (20), and the release of GH and prolactin from isolated pituitary secretory granules is increased by the presence of glutathione and other thiol-reducing agents, probably through the disruption of disulfide bonds in the hormone oligomers and/or granule membrane proteins (18, 19). It is likely that TRX enters cells (33) and that its role in GH secretion involves its strong reducing activity (10). However, because two other reducing agents, beta -mercaptoethanol and N-actyl-L-cysteine, failed to enhance GH secretion in our study, it is possible that TRX may exert its role through mechanisms other than simple reduction as well.

On the other hand, Lefrançois et al. (16) showed that reducing agents such as glutathione and dithiothreitol suppressed the coupling of GRF receptor with GRF. Other studies have also shown that the coupling of secretin or glucagon receptors with their ligands was decreased by thiol-reducing agents (17, 27, 30). Although such an inhibitory effect of TRX was not apparent in our experiments, it is possible that TRX, as well as other thiol-reducing physiological substances, has two opposing effects and regulates the GH secretion in a complex manner. Further analyses of the redox regulation of the GRF-GH axis may provide a better understanding of the characteristic pulsatile secretion of GH.


    ACKNOWLEDGEMENTS

We appreciate Dr. Manabu Inuzuka (Department of First Biochemistry, Fukui Medical University) for technical support. We also thank Dr. Yoshiki Yamamoto for providing the rat GH cDNA. RIA reagents were provided by Dr. A. F. Parlow through the National Hormone and Pituitary Program, National Institute of Diabetes and Digestive and Kidney Diseases. The recombinant human TRX was kindly provided by Aji-no-moto Central Laboratory, Japan.


    FOOTNOTES

Address for reprint requests and other correspondence: I. Hata, Dept. of Pediatrics, Fukui Medical University, Fukui 910-1193, Japan (E-mail: ikueh{at}fmsrsa.fukui-med.ac.jp).

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.

Received 23 October 2000; accepted in final form 16 March 2001.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Barinaga, M, Bilezikjian LM, Vale WW, Rosenfeld MG, and Evans RM. Independent effects of growth hormone releasing factor on growth hormone release and gene transcription. Nature 314: 279-281, 1985[ISI][Medline].

2.   Billestrup, N, Swanson LW, and Vale W. Growth hormone-releasing factor stimulates proliferation of somatotrophs in vitro. Proc Natl Acad Sci USA 83: 6854-6857, 1986[Abstract].

3.   Demarquoy, J, Fairand A, Vaillant R, and Gautier C. Development and hormonal control of thioredoxin and the thioredoxin-reductase system in the rat liver during the perinatal period. Experientia 47: 497-500, 1991[ISI][Medline].

4.   Frohman, LA, and Kineman RD. Growth hormone-releasing hormone: discovery, regulation, and actions. In: Handbook of Physiology. The Endocrine System, Hormonal Control of Growth. Bethesda, MD: Am. Physiol. Soc, 1998, sect. 7, vol. V, chapt. 8, p. 187-219.

5.   Fukata, J, Diamond DJ, and Martin JB. Effects of rat growth hormone (rGH)-releasing factor and somatostatin on the release and synthesis of rGH in dispersed pituitary cells. Endocrinology 117: 457-467, 1985[Abstract].

6.   Grippo, JH, Holmgren A, and Pratt WB. Proof that the endogenous heat-stable glucocorticoid receptor-activating factor is thioredoxin. J Biol Chem 260: 93-97, 1985[Abstract/Free Full Text].

7.  Hata I, Shigematsu Y, Tsukahara H, Fujisawa K, Nakai A, Kikawa Y, and Sudo M. Nitric oxide production from cultured rat pituitary cells after G.R.F. stimulation. In: Abstracts of the 10th Meeting of the Research Society for Growth Disturbance in Children. Tokyo, 1996, p. 55.

8.   Hayashi, S, Hajiro-Nakanishi K, Makino Y, Eguchi H, Yodoi J, and Tanaka H. Functional modulation of estrogen receptor by redox state with reference to thioredoxin as a mediator. Nucleic Acids Res 25: 4035-4040, 1997[Abstract/Free Full Text].

9.   Holmgren, A. Thioredoxin. Annu Rev Biochem 54: 237-271, 1985[ISI][Medline].

10.   Holmgren, A, and Bjornstedt M. Thioredoxin and thioredoxin reductase. Methods Enzymol 252: 199-208, 1995[ISI][Medline].

11.   Iwai, T, Fujii S, Nanbu Y, Nonogaki H, Konishi I, Mori T, Masutani H, and Yodoi J. Expression of adult T-cell leukaemia-derived factor, a human thioredoxin homologue, in the human ovary throughout the menstrual cycle. Virchows Arch 420: 213-217, 1992.

12.   Jonathan, NB, Peleg E, and Hoefer MT. Optimization of culture conditions for short term pituitary cell culture. Methods Enzymol 103: 249-257, 1983[ISI][Medline].

13.   Kato, M. Involvement of nitric oxide in growth hormone (GH)-releasing hormone-induced GH secretion in rat pituitary cells. Endocrinology 131: 2133-2138, 1992[Abstract].

14.   Kotsuji, F, Winters SJ, Keeping HS, Attardi B, Oshima H, and Troen P. Effects of inhibin from primate Sertoli cells on follicle-stimulating hormone and luteinizing hormone release by perifused rat pituitary cells. Endocrinology 122: 2796-2802, 1988[Abstract].

15.   Laurent, TC, Moore EC, and Reicahrd P. Enzymatic synthesis of deoxyribonucreotides. IV. Isolation and characterization of thioredoxin, the hydrogen donor from Echerichia coli B. J Biol Chem 239: 3436-3444, 1964[Free Full Text].

16.   Lefrançois, L, Boulanger L, and Gaudreau P. Effects of aging on pituitary growth hormone-releasing factor binding sites: in vitro mimicry by guanyl nucleotides and reducing agents. Brain Res 673: 39-46, 1995[ISI][Medline].

17.   Lipson, KE, Kolhatkar AA, Dorato A, and Donner DB. N-ethylmaleimide uncouples the glucagon receptor from the regulatory component of adenylyl cyclase. Biochemistry 25: 5678-5685, 1986[ISI][Medline].

18.   Lorenson, MY. In vitro conditions modify immunoassayability of bovine pituitary prolactin and growth hormone: insights into their secretory granule storage forms. Endocrinology 116: 1399-1407, 1985[Abstract].

19.   Lorenson, MY, and Jacobs LS. Thiol regulation of protein, growth hormone, and prolactin release from isolated adenohypophysial secretory granules. Endocrinology 110: 1164-1172, 1982[ISI][Medline].

20.   Lorenson, MY, Miska SP, and Jacobs LS. Molecular mechanism of prolactin release from pituitary secretory granules. In: Frontiers and Perspectives of Prolactin Secretion: A Multidisciplinary Approach, edited by Mena F, and Valverde CM.. New York: Academic, 1984, p. 141.

21.   Luo, D, and McKeown BA. An antioxidant dependent in vitro response of rainbow trout (Salmo gairdneri) somatotrophs to carp growth hormone-releasing factor (GRF). Horm Metab Res 21: 690-692, 1989[ISI][Medline].

22.   Makino, Y, Okamoto K, Yoshikawa N, Aoshima M, Hirota K, Yodoi J, Umesono K, Makino I, and Tanaka H. Thioredoxin: a redox-regulating cellular cofactor for glucocorticoid hormone action. J Clin Invest 98: 2469-2477, 1996[Abstract/Free Full Text].

23.   Makino, Y, Yoshikawa N, Okamoto K, Hirota K, Yodoi J, Makino I, and Tanaka H. Direct association with thioredoxin allows redox regulation of glucocorticoid receptor function. J Biol Chem 274: 3182-3188, 1999[Abstract/Free Full Text].

24.   Matthews, JR, Wakasugi N, Virelizier JL, Yodoi J, and Hay RT. Thioredoxin regulates the DNA binding activity of NF-kappa -B by reduction of a disulfide bond involving cysteine 62. Nucleic Acids Res 20: 3821-3830, 1992[Abstract].

25.   Nakamura, H, Nakamura K, and Yodoi J. Redox regulation of cellular activation. Annu Rev Immunol 15: 351-369, 1997[ISI][Medline].

27.   Ogawa, N, Mizuno S, Mori A, Nukina I, and Yanaihara N. Properties and distribution of vasoactive intestinal polypeptide receptor in the rat brain. Peptides 6: 103-109, 1985[ISI][Medline].

28.   Padilla, CA, Martinez-Galisteo E, and Barcena JA. Topological relationships between porcine anterior pituitary hormones and the thioredoxin and glutaredoxin systems. Tissue Cell 25: 937-946, 1993[ISI][Medline].

29.   Padilla, CA, Martinez-Galisteo E, Lopez-Barea J, Holmgren A, and Barcena JA. Immunolocalization of thioredoxin and glutaredoxin in mammalian hypophysis. Mol Cell Endocrinol 85: 1-12, 1992[ISI][Medline].

30.   Robberecht, P, Waelbroeck M, Camus JC, Neef P, and Christophe J. Importance of disulfide bonds in receptors for vasoactive intestinal peptide and secretin in rat pancreatic plasma membranes. Biochim Biophys Acta 773: 271-278, 1984[ISI][Medline].

31.   Sasada, T, Iwata S, Sato N, Kitaoka Y, Hirota K, Nakamura K, Nishiyama A, Taniguchi Y, Takabayashi A, and Yodoi J. Redox control of resistance to cis-diamminedichloroplatinum (II)(CDDP). Protective effect of human thioredoxin against CDDP-induced cytotoxicity. J Clin Invest 97: 2268-2276, 1996[Abstract/Free Full Text].

32.   Schreck, R, Rieber P, and Baeuerle PA. Reactive oxygen intermediates as apparently widely used messengers in the activation of the NF-kappa B transcription factor and HIV-1. EMBO J 10: 2247-2258, 1991[Abstract].

33.   Spector, A, Yan GZ, Huang RRC, Mcdermott MJ, Gascoyne PRC, and Pigiet V. The effect of H2O2 upon thioredoxin-enriched lens epitherial cells. J Biol Chem 263: 4984-4990, 1988[Abstract/Free Full Text].

34.   Stamler, JS, Singel DJ, and Loscalzo J. Biochemistry of nitric oxide and its redox-activated forms. Science 258: 1898-1902, 1992[ISI][Medline].

35.   Tannenbaum, GS, and Ling N. The interrelationship of growth hormone (GH)-releasing factor and somatostatin in generation of the ultradian rhythm if GH secretion. Endocrinology 115: 1952-1957, 1984[Abstract].

36.   Tannenbaum, GS, McCarthy GF, Zeitler P, and Beaudet A. Cysteamine-induced enhancement of growth hormone-releasing factor (GRF) immunoreactivity in arcuate neurons: morphological evidence for putative somatostatin/GRF interactions within hypothalamus. Endocrinology 127: 2551-2560, 1990[Abstract].

37.   Yamamoto, M, Sato N, Tajima H, Furuke K, Ohira A, Honda Y, and Yodoi J. Induction of human thioredoxin in cultured human retinal pigment epithelial cells through cyclic AMP-dependent pathway: involvement in the cytoprotective activity of prostaglandin E1. Exp Eye Res 65: 645-652, 1997[ISI][Medline].


Am J Physiol Endocrinol Metab 281(2):E269-E274
0193-1849/01 $5.00 Copyright © 2001 the American Physiological Society




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