Regulation of mRNA Expression of 3β-Hydroxy-5-Ene Steroid Dehydrogenase in Porcine Granulosa Cells in Culture: A Role for the Protein Kinase-C Pathway

Publisher Website
Google Scholar
Abstract
We studied the effect of the tumor-promoting phorbol ester phorbol 12-myristate 13-acetate (PMA), which activates protein kinase-C, on porcine granulosa cells in culture. PMA as well as cholera toxin, forskolin, and hCG increased cAMP accumulation. PMA further augmented the elevation in cAMP accumulation induced by cholera toxin, forskolin, and hCG. In the same cell culture model, hCG induced a time-dependent increase in the 3.beta.-hydroxy-5-ene steroid dehydrogenase (3.beta.HSD) mRNA levels with a maximal 3-fold stimulation obtained at 8-16 h of incubation with 1 IU hCG/ml. PMA inhibited the increase in 3.beta.HSD mRNA levels induced by hCG in a dose-dependent manner. The phorbol ester also inhibited the increase in 3.beta.HSD mRNA levels stimulated by LH as well as cholera toxin and forskolin and the cAMP analogs (Bu)23CAMP and 8-bromo-cAMP. Activation of protein kinase-C by mezerein similarly inhibited hCG stimulation of 3.beta.HSD mRNA levels. The present data indicate that activation of the protein kinase-C pathway induces generation of cAMP, but causes a near-complete inhibition of the stimulatory effects of hCG, LH, forskolin, cholera toxin, and cAMP analogs on 3.beta.HSD mRNA levels in porcine granulosa cells in culture.

This publication has 24 references indexed in Scilit: