Inhibition of Prostaglandin Synthesis and the Release of Vasopressin and Oxytocin from the Rat Neurohypophysis: In Vitro Studies1)

Abstract

The basal and K(+)-evoked release of vasopressin (VP) and oxytocin (OT) from the neurointermediate lobes in vitro was determined under conditions of indomethacin-induced inhibition of prostaglandin (PG) synthesis. The in vivo treatment with indomethacin (IM), administered to donor animals, did not modify the release of VP during resting conditions as well as during the potassium stimulation; on the contrary, both base-line and K(+)-evoked release of OT was significantly inhibited under such conditions. Incubation of neurointermediate lobes in a solution containing indomethacin resulted in an inhibition of VP and OT release both during resting conditions and during depolarization due to excess potassium.