Release of corticotrophin-releasing factor-41, arginine vasopressin and oxytocin from rat fetal hypothalamic cells in culture: response to activation of intracellular second messengers and to corticosteroids.

The effects of the activation of protein kinase A (PKA), protein kinase C (PKC) and corticosteroids were investigated on the release of corticotrophin-releasing factor-41 (CRF), arginine vasopressin (AVP) and oxytocin from rat fetal hypothalamic cells in culture. Both forskolin and PMA (phorbol 12-myristate 13-acetate) increased CRF, AVP and oxytocin release, while dexamethasone and aldosterone only reduced basal secretion of CRF. Both steroids also inhibited forskolin-induced CRF, AVP and oxytocin responses to PMA. These data provide direct evidence for a role for both PKC- and PKA-mediated mechanisms in the regulation of CRF, AVP and oxytocin release and for differential effects of both glucocorticoids and mineralocorticoids on PKA- and PKC-stimulated responses.