Endocrinology, Vol 137, 1187-1195, Copyright © 1996 by Endocrine Society

ARTICLES

Steroidogenic factor-1 as a positive regulator of rat granulosa cell differentiation and a negative regulator of mitosis

DB Shapiro, A Pappalardo, BA White and JJ Peluso
Department of Obstetrics, University of Connecticut Health Center, Farmington, 06030, USA.

Ovarian follicles contain small nonaromatase-expressing and large aromatase-expressing granulosa cells (GCs). The present studies were designed to determine whether small GCs can differentiate into large GCs and/or express aromatase. Additional studies were conducted to assess the role of steroidogenic factor-1 (SF-1), an orphan nuclear receptor, in regulating GC differentiation and proliferation. For these studies, small GCs were isolated from immature rats by Percoll gradient centrifugation and cultured for up to 48 h with FSH and/or 8-bromo-cAMP (8-br-cAMP). FSH/8-br-cAMP induced a 2-fold increase in SF-1 messenger RNA levels within 4 h. This increase was maintained throughout the culture period. By 24 h culture, FSH/8-br-cAMP increased the percentage of large GCs. It was not until 48 h of culture with FSH and 8-br-cAMP that aromatase expression increased. This increase was detected by both Western blot and quantitative immunocytochemistry. 8-br-cAMP alone did not promote GC differentiation. Small GCs were then cultured with FSH/8- br-cAMP in the presence or absence of an antisense oligonucleotide complementary to the putative SF-1 ligand-binding site (SF-1 AS). As a control, small GCs were cultured with FSH/8-br-cAMP and an 18-mer nonsense oligonucleotide (SF-1 NS). The SF-1 AS, but not the SF-1 NS, prevented FSH/8-br-cAMP from increasing 1) SF-1 messenger RNA levels, 2) transcription of a SF-1(x2) promoter/luciferase construct, 3) GC size, and 4) aromatase expression. In a third series of experiments, small GCs were cultured for 24 h in 1) control media supplemented with 2) a mitogen, phorbol ester [12-O-tetraphorbol acetate (TPA)], 3) FSH/8- br-cAMP, or 4) both. TPA increased the number of GCs by 51 +/- 9%. FSH/8-br-cAMP completely blocked TPA-induced mitosis. When small GCs were cultured with FSH/cAMP, TPA, and SF-1 AS, the number of GCs increased by 50 +/- 7%. This increase was not observed with SF-1 NS. Taken together, these data demonstrate that SF-1 is expressed in both small and large GCs, and enhanced SF-1 expression is part of the molecular mechanism associated with GC differentiation. Interestingly, SF-1 not only regulates differentiation, but also inhibits TPA-induced GC mitosis.

This article has been cited by other articles:

				Y Kamei, Y Aoyama, T Fujimoto, N Kenmotsu, C Kishi, M Koushi, S Sugano, K Morohashi, R Kamiyama, and R Asakai A steroidogenic cell line with differentiation potential from mouse granulosa cells, transfected with Ad4BP and SV40 large T antigen genes J. Endocrinol., April 1, 2005; 185(1): 187 - 195. [Abstract] [Full Text] [PDF]

				I. Rothchild The Yolkless Egg and the Evolution of Eutherian Viviparity Biol Reprod, February 1, 2003; 68(2): 337 - 357. [Abstract] [Full Text] [PDF]

				W. Xing and M. R. Sairam Retinoic Acid Mediates Transcriptional Repression of Ovine Follicle-Stimulating Hormone Receptor Gene via a Pleiotropic Nuclear Receptor Response Element Biol Reprod, July 1, 2002; 67(1): 204 - 211. [Abstract] [Full Text] [PDF]

				J. Levallet, P. Koskimies, N. Rahman, and I. Huhtaniemi The Promoter of Murine Follicle-Stimulating Hormone Receptor: Functional Characterization and Regulation by Transcription Factor Steroidogenic Factor 1 Mol. Endocrinol., January 1, 2001; 15(1): 80 - 92. [Abstract] [Full Text]

				J.J. Peluso and A. Pappalardo Progesterone Maintains Large Rat Granulosa Cell Viability Indirectly by Stimulating Small Granulosa Cells to Synthesize Basic Fibroblast Growth Factor Biol Reprod, February 1, 1999; 60(2): 290 - 296. [Abstract] [Full Text] [PDF]

				D. M. Nash, S. A. Hess, B. A. White, and J. J. Peluso Steroidogenic Factor-1 Regulates the Rate of Proliferation of Normal and Neoplastic Rat Ovarian Surface Epithelial Cells in Vitro Endocrinology, November 1, 1998; 139(11): 4663 - 4671. [Abstract] [Full Text] [PDF]

				A. Amsterdam and N. Selvaraj Control of Differentiation, Transformation, and Apoptosis in Granulosa Cells by Oncogenes, Oncoviruses, and Tumor Suppressor Genes Endocr. Rev., August 1, 1997; 18(4): 435 - 461. [Abstract] [Full Text] [PDF]

				K. L. Parker and B. P. Schimmer Steroidogenic Factor 1: A Key Determinant of Endocrine Development and Function Endocr. Rev., June 1, 1997; 18(3): 361 - 377. [Abstract] [Full Text]

				M. S. Ramayya, J. Zhou, T. Kino, J. H. Segars, C. A. Bondy, and G. P. Chrousos Steroidogenic Factor 1 Messenger Ribonucleic Acid Expression in Steroidogenic and Nonsteroidogenic Human Tissues: Northern Blot and in Situ Hybridization Studies J. Clin. Endocrinol. Metab., June 1, 1997; 82(6): 1799 - 1806. [Abstract] [Full Text] [PDF]

				D. L. Carlone and J. S. Richards Functional Interactions, Phosphorylation, and Levels of 3',5'-Cyclic Adenosine Monophosphate-Regulatory Element Binding Protein and Steroidogenic Factor-1 Mediate Hormone-Regulated and Constitutive Expression of Aromatase in Gonadal Cells Mol. Endocrinol., March 1, 1997; 11(3): 292 - 304. [Abstract] [Full Text]