title: Assessment of the luteolytic potency of various prostaglandins in the pseudopregnant rabbit.
abstract: The ability of systemic infusion of arachidonic acid and various prostaglandin (PG) compounds to induce luteolysis was examined in the Day 9 pseudopregnant rabbit. Administration of PGF-2 alpha (25 microgram/h for 6 h) elicited a decline in plasma progesterone from mean +/- s.e.m. pretreatment levels of 8.83 +/- 0.54 to 0.54 +/- 0.05 ng/ml on the following day (P less than 0.01). A shorter infusion (25 microgram/h for 3 h) or a lower hourly dose rate (12.5 microgram/h for 6 h) of PGF-2 alpha was ineffectual, suggesting that a dose/duration regimen exists for PGF-2 alpha-mediated luteolysis. PGE-2 (25 microgram/h for 6 h) or sodium arachidonate (667 microgram/h for 6 h) did not significantly affect luteal function. Of the PGF-2 alpha metabolites examined, 13,14-dihydro-PGF-2 alpha was the most effective: it was approximately 4-fold more potent as a luteolysin than PGF-2 alpha since functional regression occurred with infusion of 6.25 microgram/h for 6 h. These data illustrate that systemic infusion of PGF-2 alpha is capable of inducing luteolysis in the rabbit. The metabolite 13,14-dihydro-PGF-2 alpha may also be involved luteolytically in this species.
mesh_terms: D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D005260:Female; D003341:Luteolysis / Q000187:drug effects*; D011374:Progesterone / Q000097:blood; D011458:Prostaglandins E / Q000494:pharmacology*; D011460:Prostaglandins F / Q000494:pharmacology*; D011555:Pseudopregnancy; D011817:Rabbits; D011863:Radioimmunoassay
chemical_list: D001095:Arachidonic Acids; D011458:Prostaglandins E; D011460:Prostaglandins F; D011374:Progesterone