P450scc regulation in pig granulosa cells: investigation into the mechanism of induction.

P450scc catalyses the first and rate-limiting reaction in steroidogenesis and is hormonally regulated. By Northern analysis, using a bovine cDNA probe, we have studied the regulation of P450scc mRNA in pig granulosa cells cultivated in vitro. Using transcription and translation inhibitors, we show that the gonadotropin-induced accumulation of P450scc mRNA mainly results from increased transcription, and that this stimulation, at least in part, is protein synthesis-dependent. Although transcriptional regulation of P450scc gene expression is found in other steroidogenic cells, cycloheximide-sensitivity of this regulation is not widespread. Pig granulosa cells thus would constitute a useful model to study this mechanism of regulation.