REGULATION OF C-FOS MESSENGER-RNA EXPRESSION IN SERTOLI CELLS BY CYCLIC-AMP, CALCIUM, AND PROTEIN-KINASE-C MEDIATED PATHWAYS

The role of second messenger pathways, cyclic AMP, calcium, and protei n kinase C (PKC) in the transcriptional regulation of c-fos protooncog ene expression in rat Sertoli cells was investigated. c-fos expression was monitored by Northern blot analysis. Although the action of FSH o n Sertoli cells is considered to be mediated by cAMP, dibutyryl cAMP ( dbcAMP), a potent membrane permeable analog of cAMP, induced much less c-fos mRNA expression than FSH (<50%) suggesting that additional cAMP -independent mechanisms may mediate the effect of FSH on c-fos. Specif ic intracellular inhibitors of PKC decreased c-fos induction in respon se to FSH by more than 50%. Ionomycin, which increases intracellular f ree calcium concentration, induced c-fos expression significantly. The se data demonstrate that Sertoli cell c-fos mRNA expression is under m ultifactorial regulation by cAMP, calcium, and PKC.