Receptor mediated gonadotropin action in the ovary. Modulation of progesterone response in isolated rat ovarian cells by gonadotrophin, cholera enterotoxin and cyclic nucleotides: requirement for RNA and protein synthesis
Azhar, S.; Menon, M.; Menon, K.M.
Acta Endocrinologica 95(4): 528-539
1980
ISSN/ISBN: 0001-5598 PMID: 6161508 Document Number: 161864
The role of macromolecular synthesis in gonadotropin, cholera enterotoxin and cAMP-stimulated progesterone production by rat ovarian cells was investigated. Both progesterone and cAMP accumulation were increased by cholera enterotoxin in a concentration-dependent manner. Incubation of cells with cholera enterotoxin resulted in a 10- to 20-fold increase in cAMP levels. The effect was observed 15-20 min after addition of toxin. In contrast, stimulation of cAMP levels by hCG proline incorporation and the lack of effect of these inhibitors on cAMP production in response to hCG, LH and cholera enterotoxin. Emetine (10 .mu.M) and cycloheximide (50 .mu.M) inhibited cholera enterotoxin and hCG-stimulated progesterone production when added at different time points during the incubation. Cordycepin (250 .mu.M) also blocked toxin and hCG-induced steroidogenesis in a similar manner. The concentrations of cordycepin, cycloheximide and emetine required to completely block hCG-stimulated progesterone production were 250, 50 and 5 .mu.M, respectively. Similar concentrations of these inhibitors also maximally inhibited 8 Br-cAMP and cholera enterotoxin stimulated steroidogenesis. No effect of these inhibitors on basal production of progesterone was observed. These results suggest that gonadotropin-induced progesterone synthesis is dependent upon the continued synthesis of short lived mRNA and protein(s).