The possible involvement of cytochrome P-450 monooxygenase in AVP-induced ACTH secretion

AVP (10(-7) M) induced ACTH as well as PGE2 release from rat anterior pituitary quarters. Inhibitors of P-450 monooxygenase, metyrapone (10 mM) and piperonyl butoxide (1 mM and 10 mM) attenuated the ACTH and PGE2 response to AVP. 7,8-benzoflavon (10 mM) which inhibits 3-methylchloranthrene inducible form of P-450 isoenzymes showed no inhibition of AVP-induced ACTH secretion. The decrease in ACTH response to AVP was still observed following the inhibition of prostaglandin synthesis by indomethacin. These results suggest that cytochrome P-450 monoocygenase systems are involved in the process of AVP-induced ACTH secretion, 3-methylchloranthrene inducible form of P-450 isoenzymes do not seem to be involved in this process.