Journal of Clinical Endocrinology & Metabolism, Vol 79, 1670-1677, Copyright © 1994 by Endocrine Society

ARTICLES

Regulation of inhibin alpha- and beta A-subunit messenger ribonucleic acid levels by chorionic gonadotropin and recombinant follicle- stimulating hormone in cultured human granulosa-luteal cells

M Eramaa, T Tuuri, K Hilden and O Ritvos
Department of Bacteriology and Immunology, University of Helsinki, Finland.

We studied the effects of recombinant human FSH (rhFSH) and purified hCG on the steady state messenger ribonucleic acid (mRNA) levels of inhibin alpha- and beta A-subunits in cultured granulosa-luteal cells of preovulatory ovarian follicles obtained from women undergoing in vitro fertilization. Specific mRNA transcripts for the alpha- and beta A-subunits were detected in Northern and dot blot filter hybridization analyses, and the levels of these mRNAs were induced by rhFSH and hCG in a distinct concentration- and time-dependent manner. The basal and hCG-stimulated alpha-subunit mRNA levels were first determined at 2- to 3-day intervals over a 3- to 10-day culture period after the initiation of the cultures. Both the basal and hCG-stimulated alpha-subunit mRNA levels declined steadily during culture, but the maximal relative stimulatory effect of hCG was observed on day 7 of culture. All subsequent experiments, therefore, were performed on days 6-8 of culture. Both gonadotropins induced alpha-subunit mRNA levels with slower kinetics than those of the beta A-subunit. Varying between experiments, rhFSH and hCG increased the expression of the alpha- subunit with a maximal effect of 2.5- to 5.7-fold and 1.7- to 7.2-fold, respectively, above basal levels 24-48 h after stimulation. rhFSH and hCG induced beta A-subunit mRNA levels with 3.0- to 5.8-fold and 2.3- to 8.6-fold increases above basal levels, respectively, at 2 h; thereafter, only moderate or no stimulation of the beta A-subunit mRNA levels could be detected at 7-48 h. Treatment of the cells with the RNA synthesis inhibitor actinomycin-D prevented the induction of alpha- subunit mRNA levels by hCG, and no significant differences were detected in the stability of alpha-subunit mRNA transcripts in hCG- treated cells vs. untreated cultures. This indicates that hCG induces transcription of the alpha-subunit gene rather than maintains the levels of preexisting transcripts. As the kinetics of induction of alpha- and beta A-subunit mRNAs by gonadotropins were different, we examined how the inhibition of protein synthesis affects the induction of alpha- and beta A-subunit mRNAs by hCG. Cycloheximide had no effect on basal alpha-subunit mRNA levels at 2 or 24 h. However, it inhibited at 24 h the induction of the alpha-subunit by hCG.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				Y. Wang and W. Ge Involvement of Cyclic Adenosine 3',5'-Monophosphate in the Differential Regulation of Activin {beta}A and {beta}B Expression by Gonadotropin in the Zebrafish Ovarian Follicle Cells Endocrinology, February 1, 2003; 144(2): 491 - 499. [Abstract] [Full Text] [PDF]

				R. Jaatinen, J. Bondestam, T. Raivio, K. Hilden, L. Dunkel, N. Groome, and O. Ritvos Activation of the Bone Morphogenetic Protein Signaling Pathway Induces Inhibin {beta}B-Subunit mRNA and Secreted Inhibin B Levels in Cultured Human Granulosa-Luteal Cells J. Clin. Endocrinol. Metab., March 1, 2002; 87(3): 1254 - 1261. [Abstract] [Full Text] [PDF]

				T. Fujiwara, Y. Sidis, C. Welt, G. Lambert-Messerlian, J. Fox, A. Taylor, and A. Schneyer Dynamics of Inhibin Subunit and Follistatin mRNA during Development of Normal and Polycystic Ovary Syndrome Follicles J. Clin. Endocrinol. Metab., September 1, 2001; 86(9): 4206 - 4215. [Abstract] [Full Text] [PDF]

				M. Fawzy, R.F. Harrison, P.G. Knight, N. Groome, A. Anderson, W.R. Robertson, and A. Lambert The effect of gonadotrophins with differing LH/FSH ratios on the secretion of the various species of inhibin in women receiving IVF Hum. Reprod., June 1, 2001; 16(6): 1092 - 1097. [Abstract] [Full Text] [PDF]

				J. Liu, C. Hyden-Granskog, and R. Voutilainen Gonadotrophins inhibit and activin induces expression of inhibin/activin {beta}B subunit mRNA in cultured human granulosa-luteal cells Mol. Hum. Reprod., April 1, 2001; 7(4): 319 - 323. [Abstract] [Full Text] [PDF]

				C. K. Welt and A. L. Schneyer Differential Regulation of Inhibin B and Inhibin A by Follicle-Stimulating Hormone and Local Growth Factors in Human Granulosa Cells from Small Antral Follicles J. Clin. Endocrinol. Metab., January 1, 2001; 86(1): 330 - 336. [Abstract] [Full Text]

				C.-H. Chiang, K. W. Cheng, S. Igarashi, P. S. Nathwani, and P. C. K. Leung Hormonal Regulation of Estrogen Receptor {alpha} and {beta} Gene Expression in Human Granulosa-Luteal Cells in Vitro J. Clin. Endocrinol. Metab., October 1, 2000; 85(10): 3828 - 3839. [Abstract] [Full Text]

				C. K. Welt, J. M. Adams, P. M. Sluss, and J. E. Hall Inhibin A and Inhibin B Responses to Gonadotropin Withdrawal Depends on Stage of Follicle Development J. Clin. Endocrinol. Metab., June 1, 1999; 84(6): 2163 - 2169. [Abstract] [Full Text]

				G. M. Lanuza, N. P. Groome, J. L. Barañao, and S. Campo Dimeric Inhibin A and B Production Are Differentially Regulated by Hormones and Local Factors in Rat Granulosa Cells Endocrinology, June 1, 1999; 140(6): 2549 - 2554. [Abstract] [Full Text]

				M. Laitinen, A. RistimAki, M. Honkasalo, K. Narko, K. Paavonen, and O. Ritvos Differential Hormonal Regulation of Vascular Endothelial Growth Factors VEGF, VEGF-B, and VEGF-C Messenger Ribonucleic Acid Levels in Cultured Human Granulosa-Luteal Cells Endocrinology, November 1, 1997; 138(11): 4748 - 4756. [Abstract] [Full Text] [PDF]

				K. Narko, O. Ritvos, and A. Ristimaki Induction of Cyclooxygenase-2 and Prostaglandin F2{alpha} Receptor Expression by Interleukin-1{beta} in Cultured Human Granulosa-Luteal Cells Endocrinology, September 1, 1997; 138(9): 3638 - 3644. [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]

				C. K. Welt, K. A. Martin, A. E. Taylor, G. M. Lambert-Messerlian, W. F. Crowley Jr., J. A. Smith, D. A. Schoenfeld, and J. E. Hall Frequency Modulation of Follicle-Stimulating Hormone (FSH) during the Luteal-Follicular Transition: Evidence for FSH Control of Inhibin B in Normal Women J. Clin. Endocrinol. Metab., August 1, 1997; 82(8): 2645 - 2652. [Abstract] [Full Text] [PDF]

				A. Ristimaki, R. Jaatinen, and O. Ritvos Regulation of Prostaglandin F2{alpha} Receptor Expression in Cultured Human Granulosa-Luteal Cells Endocrinology, January 1, 1997; 138(1): 191 - 195. [Abstract] [Full Text] [PDF]