Relaxin inhibits prostacyclin release by the rat pregnant myometrium.
Porcine relaxin (30 microgram/ml) when incubated with separated myometrial tissue from 20 day pregnant rats inhibited basal prostacyclin output by 50%. However, relaxin did not inhibit the increased prostacyclin output observed when myometrial tissue was incubated with the prostaglandin precursor, arachidonic acid (10 microgram/ml). When prostacyclin release was stimulated by incubation with oxytocin (10 mU/ml), however, relaxin completely inhibited the increased output. The results suggest that relaxin interferes with basal and oxytocin-stimulated prostacyclin formation in pregnant myometrial tissue by inhibiting the action of the enzyme phospholipase A2 which is responsible for liberating the precursor arachidonic acid endogenously.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D009215:Myometrium / Q000187:drug effects / Q000378:metabolism*; D010121:Oxytocin / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D011247:Pregnancy; D011270:Pregnancy, Animal; D011453:Prostaglandins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012065:Relaxin / Q000494:pharmacology*; D013552:Swine; D014599:Uterus / Q000378:metabolism*
D001095:Arachidonic Acids; D011453:Prostaglandins; D016718:Arachidonic Acid; D010121:Oxytocin; D000244:Adenosine Diphosphate; D012065:Relaxin; D011464:Epoprostenol