| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Endocrinology, Vol 115, 183-190, Copyright © 1984 by Endocrine Society
ARTICLES |
EY Adashi and CE Resnick
The intermediary role of cAMP in the mechanism of action of FSH was reinvestigated in vitro using forskolin, a highly specific adenylate cyclase probe. Granulosa cells from immature hypophysectomized diethylstilbestrol-treated rats were cultured for 3 days in the absence or presence of forskolin. Treatment with increasing concentrations (10(- 7)-10(-4) M) of forskolin led to dose-dependent increments in the accumulation of extracellular cAMP, with an apparent median effective dose of 1.6 +/- 0.5 X 10(-5) M. Concomitant blockade of cAMP phosphodiesterase activity further enhanced the forskolin effect. Treatment with forskolin also brought about dose- and time-dependent increments in progesterone and estrogen accumulation. Granulosa cells not pretreated with forskolin displayed negligible LH/hCG binding and remained unresponsive to luteotropic (LH/hCG), beta 2-adrenergic (terbutaline), or lactogenic (PRL) stimulation. In contrast, forskolin (10(-5) M)-pretreated granulosa cells displayed significant increases over controls in LH/hCG binding (46-fold) as well as in progesterone accumulation stimulated by hCG (3.3-fold), terbutaline (1.9-fold), and PRL (1.8-fold). Furthermore, concomitant treatment with a functionally inert low dose (10(-7) M) of forskolin, substantially potentiated the FSH-stimulated accumulation of extracellular cAMP, progesterone, and estrogen as well as the FSH-mediated increase in LH/hCG binding. Taken together, our findings indicate that forskolin, like FSH, is capable of inducing the differentiation of cultured rat granulosa cells by itself, and that a functionally inert low dose of forskolin can potentiate FSH hormonal action. Inasmuch as forskolin-simulated and forskolin- potentiated hormonal action are acceptable as novel criteria of cAMP dependence, our findings provide new evidence in support of the notion that cAMP may be an intracellular second messenger of FSH.
This article has been cited by other articles:
![]() |
E. Y. Adashi, C. E. Resnick, D. W. Payne, R. G. Rosenfeld, T. Matsumoto, M. K. Hunter, S. E. Gargosky, J. Zhou, and C. A. Bondy The Mouse Intraovarian Insulin-Like Growth Factor I System: Departures from the Rat Paradigm Endocrinology, September 1, 1997; 138(9): 3881 - 3890. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |