Endocrinology, Vol 133, 2554-2560, Copyright © 1993 by Endocrine Society

ARTICLES

Activin-A regulates follistatin secretion from cultured rat anterior pituitary cells

LM Bilezikjian, AZ Corrigan, JM Vaughan and WM Vale
Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037.

The activin-binding protein, follistatin (FS), was immunoprecipitated from metabolically labeled rat anterior pituitary cells or their media using a specific antiserum to purified porcine FS (anti-FS). Several immunoreactive proteins, including one that had a mobility in the range of 42-44 kilodaltons (kDa), were detected in the cell lysates. When immunoprecipitates of the culture medium were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis, a broad 35- to 46- kDa or 39- to 53-kDa band was visualized under unreducing or reducing conditions, respectively. Upon deglycosylation by treatment with N- glycosidase-F, the secreted product migrated as a sharp protein band with an apparent size of 35 kDa. The identity or the relatedness of the immunoprecipitated proteins to FS was verified by the ability of the C- terminally truncated form of recombinant human FS (rhFS288) to compete for binding to anti-FS. When the cultured rat anterior pituitary cells were treated with either forskolin or 12-O-tetradecanoylphorbol acetate, the accumulation of FS in the culture medium was stimulated by approximately 2.5-fold. These observations suggest that the activation of either the protein kinase A or the protein kinase C signaling pathway has a stimulatory effect on anterior pituitary FS production. A more dramatic stimulation of FS secretion (up to 7-fold) was observed when the rat anterior pituitary cells were treated with activin-A. The concentration dependence for this effect was within the same range that has been reported for most of the actions of activin-A. Inhibin-A suppressed basal FS secretion and blocked its stimulation by activin-A. To determine if locally produced FS exerts an influence on the response of gonadotropes to activins, the effects of anti-FS on FSH secretion were monitored. The ability of this FS antiserum to immunoneutralize the activity of FS was initially confirmed; anti-FS attenuated the inhibitory action of exogenous follistatin on FSH secretion. Treatment of cells with the antiserum increased the apparent sensitivity of gonadotropes to submaximal concentrations of activin-A. Moreover, the presence of the antiserum lowered the concentration of activin-A that was required to produce the maximum amount of FSH secretion, without changing the magnitude of the response. These results suggested that locally produced FS interferes with the secretory response of gonadotropes to activins. Changes in locally secreted FS may, therefore, represent a mechanism by which the response of rat anterior pituitary cells to incoming stimuli are tightly regulated.

This article has been cited by other articles:

				A. L. Blount, J. M. Vaughan, W. W. Vale, and L. M. Bilezikjian A Smad-binding Element in Intron 1 Participates in Activin-dependent Regulation of the Follistatin Gene J. Biol. Chem., March 14, 2008; 283(11): 7016 - 7026. [Abstract] [Full Text] [PDF]

				G. F Y Cheng, C.-W. Yuen, and W. Ge Evidence for the existence of a local activin follistatin negative feedback loop in the goldfish pituitary and its regulation by activin and gonadal steroids J. Endocrinol., December 1, 2007; 195(3): 373 - 384. [Abstract] [Full Text] [PDF]

				W. Zheng, M. Jimenez-Linan, B. S. Rubin, and L. M. Halvorson Anterior Pituitary Gene Expression with Reproductive Aging in the Female Rat Biol Reprod, June 1, 2007; 76(6): 1091 - 1102. [Abstract] [Full Text] [PDF]

				L. M Bilezikjian, A. L Blount, C. J Donaldson, and W. W Vale Pituitary actions of ligands of the TGF-{beta} family: activins and inhibins. Reproduction, August 1, 2006; 132(2): 207 - 215. [Abstract] [Full Text] [PDF]

				C. A. Harrison, P. C. Gray, W. H. Fischer, C. Donaldson, S. Choe, and W. Vale An Activin Mutant with Disrupted ALK4 Binding Blocks Signaling via Type II Receptors J. Biol. Chem., July 2, 2004; 279(27): 28036 - 28044. [Abstract] [Full Text] [PDF]

				K. A. Prendergast, L. L. Burger, K. W. Aylor, D. J. Haisenleder, A. C. Dalkin, and J. C. Marshall Pituitary Follistatin Gene Expression in Female Rats: Evidence That Inhibin Regulates Transcription Biol Reprod, February 1, 2004; 70(2): 364 - 370. [Abstract] [Full Text] [PDF]

				A. M. O. Leal, K. Takabe, L. Wang, C. J. Donaldson, L. A. MacConell, L. M. Bilezikjian, I. M. Verma, and W. Vale Effect of Adenovirus-Mediated Overexpression of Follistatin and Extracellular Domain of Activin Receptor Type II on Gonadotropin Secretion in Vitro and in Vivo Endocrinology, March 1, 2002; 143(3): 964 - 969. [Abstract] [Full Text] [PDF]

				H.-J. Huang, J. Sebastian, B. D. Strahl, J. C. Wu, and W. L. Miller Transcriptional Regulation of the Ovine Follicle-Stimulating Hormone-{beta} Gene by Activin and Gonadotropin-Releasing Hormone (GnRH): Involvement of Two Proximal Activator Protein-1 Sites for GnRH Stimulation Endocrinology, June 1, 2001; 142(6): 2267 - 2274. [Abstract] [Full Text] [PDF]

				L. M. Bilezikjian, A. Z. Corrigan, A. L. Blount, Y. Chen, and W. W. Vale Regulation and Actions of Smad7 in the Modulation of Activin, Inhibin, and Transforming Growth Factor-{{beta}} Signaling in Anterior Pituitary Cells Endocrinology, March 1, 2001; 142(3): 1065 - 1072. [Abstract] [Full Text] [PDF]

				M. Baratta, L.A. West, A.M. Turzillo, and T.M. Nett Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion of Follicle-Stimulating Hormone in Ovine Pituitary Cells Biol Reprod, February 1, 2001; 64(2): 714 - 719. [Abstract] [Full Text]

				E. Y. Wang, L. B. Draper, E. Lee, A. Polak, P. Sluss, J. Weiss, and T. K. Woodruff Identification of Naturally Occurring Follistatin Complexes in Human Biological Fluids Biol Reprod, January 1, 1999; 60(1): 8 - 13. [Abstract] [Full Text]

				A. C. Dalkin, D. J. Haisenleder, J. T. Gilrain, K. Aylor, M. Yasin, and J. C. Marshall Regulation of Pituitary Follistatin and Inhibin/Activin Subunit Messenger Ribonucleic Acids (mRNAs) in Male and Female Rats: Evidence for Inhibin Regulation of Follistatin mRNA in Females Endocrinology, June 1, 1998; 139(6): 2818 - 2823. [Abstract] [Full Text] [PDF]

				S. J. Winters, A. C. Dalkin, and T. Tsujii Evidence That Pituitary Adenylate Cyclase Activating Polypeptide Suppresses Follicle-Stimulating Hormone-{beta} Messenger Ribonucleic Acid Levels by Stimulating Follistatin Gene Transcription Endocrinology, October 1, 1997; 138(10): 4324 - 4329. [Abstract] [Full Text] [PDF]