title: Inhibitory action of epidermal growth factor on progesterone biosynthesis in hen granulosa cells during short term culture: two sites of action.
abstract: The acute effect of epidermal growth factor (EGF) on progesterone biosynthesis by hen granulosa cells in short term culture was investigated. Pretreatment of cells for 5 h with EGF at concentrations of 1000-4000 ng/ml inhibited LH-stimulated progesterone production by 54%. Shorter EGF pretreatment times of 1 and 3 h caused 25% and 35% inhibition of LH-stimulated progesterone production, respectively. In additional experiments, EGF was found to inhibit progesterone production in response to 8-bromo-cAMP (1 mM) and forskolin (100 microM) by 34% and 35%, respectively. EGF had no effect on the conversion of 25-hydroxy-cholesterol or pregnenolone to progesterone, indicating that one site at which EGF inhibits progesterone biosynthesis is distal to cAMP generation, but before the side-chain cleavage step. EGF also inhibited LH-stimulated cAMP production by 32%, but had no effect on forskolin-stimulated cAMP accumulation. This indicated that there was a second site of EGF action in these cells, probably at the level of LH receptor coupling to the adenylate cyclase. Nerve growth factor (4000 ng/ml) had no effect on progesterone production, but fibroblast growth factor (4000 ng/ml) facilitated LH-stimulated progesterone production. The results demonstrate that the acute inhibitory effect of EGF on LH-stimulated progesterone biosynthesis in hen granulosa cells is due to its action at two sites: one at a site before the production of cAMP and the other at a step beyond cAMP generation.
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002645:Chickens; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D006107:Granulosa Cells / Q000378:metabolism*; D006888:Hydroxycholesterols / Q000378:metabolism; D007986:Luteinizing Hormone / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology; D010060:Ovulation; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*
chemical_list: D006888:Hydroxycholesterols; D009414:Nerve Growth Factors; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D011374:Progesterone; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor; D011284:Pregnenolone; C007997:25-hydroxycholesterol; D007986:Luteinizing Hormone; D000242:Cyclic AMP