Inhibitory action of somatostatin-14 on hormone-stimulated cyclic adenosine monophosphate induction in porcine granulosa and luteal cells.

Somatostatin-14 (SRIF-14) inhibited, in a concentration-dependent manner, LH- and forskolin-stimulated cyclic adenosine monophosphate (cAMP) induction in porcine granulosa and luteal cells. The inhibitory effect of SRIF-14 on hormone-induced cAMP generation was more potent in porcine ovarian cells than in the GH-3 pituitary cell line. The inhibitory effect of SRIF-14 was impeded by neutralizing its biological activity with specific antiserum. Preincubation of luteal and granulosa cells with phorbol 12-myristate 13-acetate (PMA) enhanced LH- and forskolin-stimulated cAMP levels. SRIF-14 failed to inhibit LH- or forskolin-stimulated cAMP levels in cells preincubated with PMA. It is concluded that SRIF-14 inhibits hormone-stimulated cAMP induction in the porcine ovary. LH-induced protein kinase C activation may be physiologically important to alleviate the inhibitory effects of SRIF-14.