Potentiation of prostaglandin E2-induced release of LH by the prostaglandin analogue, 7-oxa-13-prostynoic acid

Publisher Website
Google Scholar
Abstract
The prostaglandin (PG) analog 7-oxa-13-prostynoic acid (7-OPA) was infused into a lateral ventricle of the brain of adult male rats and the effect of the analog on a subsequent stimulation of LH [luteinizing hormone] release by intraventricular infusion of PG was determined. Pretreatment of the animals with 44-132 .mu.g of 7-OPA potentiated the stimulatory effect of 2 .mu. PGE2 on the release of LH but the analog alone had no effect on the hormone secretion. The minimal effective dose of PGE2 was determined to be within the range 0.01-0.05 .mu.g and priming with 132 .mu.g of 7-OPA caused a formerly sub-threshold dose (0.01 .mu.g) of PGE2 to become an effective stimulus for the release of LH. In contrast to its potentiating effect on PGE2-induced LH release, 7-OPA did not alter the stimulatory action of PGF2.alpha. (2 .mu.g) on the secretion of LH. 7-OPA had no effect on LHRH-induced release of LH, indicating that the PG analog acts at a suprapituitary site to enhance PGE2-induced LH release. The potentiating effect of 7-OPA may be exerted at a binding site for PGE2 in the brain and the results suggest the existence of a different binding site for PGF2.alpha.. The possibility also exists that 7-OPA inhibit metabolic inactivation of PGE2.