Endocrinology, Vol 127, 2804-2811, Copyright © 1990 by Endocrine Society

ARTICLES

Transforming growth factor-beta 1 inhibits ovarian androgen production: gene expression, cellular localization, mechanisms(s), and site(s) of action

ER Hernandez, A Hurwitz, DW Payne, AM Dharmarajan, AF Purchio and EY Adashi
Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore 21201.

It is the aim of this study to establish ovarian transforming growth factor-beta 1 (TGF beta 1) gene expression, to reevaluate its cellular localization, and to explore potential interactions of this regulatory peptide on ovarian androgen biosynthesis. Northern analysis of whole ovarian polyadenylated RNA revealed a single 2.5-kilobase transcript corresponding to the TGF beta 1 precursor. Immunohistochemical staining localized the protein to the thecal-interstitial (interfollicular) compartment. To explore potential autocrine effects of TGF beta 1, use was made of whole ovarian dispersates from immature rats the differentiation of which was monitored by the acquisition of androgen biosynthetic capacity. The accumulation of androsterone, the major androgenic steroid detectable in this culture system, increased 5.4- fold over baseline in response to treatment with hCG (1 ng/ml). This effect was further optimized (2- to 4-fold) by supplementation with insulin (1 microgram/ml) and insulin-like growth factor-I (50 ng/ml). In the absence of these optimizing supplements, TGF beta 1 (10 ng/ml) was without effect on basal androsterone accumulation, producing distinct, albeit relatively limited (25%), inhibition of hCG hormonal action. In contrast, supplement-mediated optimization of ovarian androgen biosynthesis revealed TGF beta 1 to be a highly potent inhibitor (greater than 80%) of hCG hormonal action. This reversible TGF beta 1 action proved time and dose dependent, with a minimal time requirement of 72 h and a median inhibitory dose of 2.6 ng/ml. TGF beta 1 action was not due to diminution in the viable cell mass or altered cAMP generation and, therefore, most likely involved a site(s) of action distal to or independent of cAMP generation. Cellular radiolabeling studies of TGF beta 1-treated ovarian cells disclosed the accumulation of steroid intermediates proximal to the 17 alpha- hydroxylation step, suggesting TGF beta 1-mediated blockade at the level of the steroidogenic enzyme 17 alpha-hydroxylase/17-20-lyase. Taken together, these observations are in keeping with the view that TGF beta 1, possibly of thecal-interstitial origin, may not only play a positive paracrine role at the level of the adjacent granulosa cell (as previously reported), but may also constitute one of several autocrine signals concerned with the regulation of ovarian androgen economy. As such, these findings reaffirm the polyfunctional nature of TGF beta 1 action, as manifested by its diametrically opposed effects in different ovarian compartments.

This article has been cited by other articles:

				J. Smitz, A.N. Andersen, P. Devroey, J.-C. Arce, and for the MERIT Group Endocrine profile in serum and follicular fluid differs after ovarian stimulation with HP-hMG or recombinant FSH in IVF patients Hum. Reprod., March 1, 2007; 22(3): 676 - 687. [Abstract] [Full Text] [PDF]

				F. Taniguchi, J. F. Couse, K. F. Rodriguez, J. M. A. Emmen, D. Poirier, and K. S. Korach Estrogen receptor-{alpha} mediates an intraovarian negative feedback loop on thecal cell steroidogenesis via modulation of Cyp17a1 (cytochrome P450, steroid 17{alpha}-hydroxylase/17,20 lyase) expression FASEB J, February 1, 2007; 21(2): 586 - 595. [Abstract] [Full Text] [PDF]

				A. De, J.-I. Park, K. Kawamura, R. Chen, C. Klein, R. Rauch, S. M. Mulders, M. D. Sollewijn Gelpke, and A. J. W. Hsueh Intraovarian Tumor Necrosis Factor-Related Weak Inducer of Apoptosis/Fibroblast Growth Factor-Inducible-14 Ligand-Receptor System Limits Ovarian Preovulatory Follicles from Excessive Luteinization Mol. Endocrinol., October 1, 2006; 20(10): 2528 - 2538. [Abstract] [Full Text] [PDF]

				A. Drummond and J. Findlay Focus on TGF-{beta} signalling. Reproduction, August 1, 2006; 132(2): 177 - 178. [Full Text] [PDF]

				I. Ben-Ami, S. Freimann, L. Armon, A. Dantes, R. Ron-El, and A. Amsterdam Novel function of ovarian growth factors: combined studies by DNA microarray, biochemical and physiological approaches Mol. Hum. Reprod., July 1, 2006; 12(7): 413 - 419. [Abstract] [Full Text] [PDF]

				J.L. Juengel and K.P. McNatty The role of proteins of the transforming growth factor-{beta} superfamily in the intraovarian regulation of follicular development Hum. Reprod. Update, March 1, 2005; 11(2): 144 - 161. [Abstract] [Full Text] [PDF]

				X. Gueripel, M. Benahmed, and A. Gougeon Sequential Gonadotropin Treatment of Immature Mice Leads to Amplification of Transforming Growth Factor {beta} Action, Via Upregulation of Receptor-Type 1, Smad 2 and 4, and Downregulation of Smad 6 Biol Reprod, March 1, 2004; 70(3): 640 - 648. [Abstract] [Full Text] [PDF]

				G. Kohli, S. Hu, E. Clelland, T. Di Muccio, J. Rothenstein, and C. Peng Cloning of Transforming Growth Factor-{beta}1 (TGF-{beta}1) and Its Type II Receptor from Zebrafish Ovary and Role of TGF-{beta}1 in Oocyte Maturation Endocrinology, May 1, 2003; 144(5): 1931 - 1941. [Abstract] [Full Text] [PDF]

				L. A. MacConell, A. M. O. Leal, and W. W. Vale The Distribution of Betaglycan Protein and mRNA in Rat Brain, Pituitary, and Gonads: Implications for a Role for Betaglycan in Inhibin-Mediated Reproductive Functions Endocrinology, March 1, 2002; 143(3): 1066 - 1075. [Abstract] [Full Text] [PDF]

				J. Qu, P. A. Godin, M. Nisolle, and J. Donnez Expression of receptors for insulin-like growth factor-I and transforming growth factor-{beta} in human follicles Mol. Hum. Reprod., February 1, 2000; 6(2): 137 - 145. [Abstract] [Full Text] [PDF]