Potentiation of prostaglandin E2-induced release of LH by the prostaglandin analogue, 7-oxa-13-prostynoic acid.
The prostaglandin (PG) analogue 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 analogue on the subsequent stimulation of LH release by intraventricular infusion of PG's was determined. Pretreatment of the animals with 44- 132 micrograms of 7-OPA potentiated the stimulatory effect of 2 micrograms PGE2 on the release of LH but the analogue 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 micrograms and it was found that priming with 132 micrograms of 7-OPA caused a formerly sub-threshold dose (0.01 micrograms) 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 micrograms) on the secretion of LH. 7-OPA had no effect on LRH-induced release of LH indicating that PG analogue 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.
D000818:Animals; D001921:Brain / Q000378:metabolism; D004357:Drug Synergism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D011458:Prostaglandins E / Q000494:pharmacology*; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011982:Receptors, Prostaglandin / Q000187:drug effects*
D005231:Fatty Acids, Unsaturated; D011458:Prostaglandins E; D011956:Receptors, Cell Surface; D011982:Receptors, Prostaglandin; C031129:7-oxa-13-prostynoic acid; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone