title: Production of prostaglandin Falpha in ewes following luteal regression induced with a prostaglandin analogue, Estrumate (cloprostenol; I.C.I. 80996).
abstract: A single injection (100 mug i.m.) of Estrumate (I.C.I. 80996) was used to induce luteal regression on day 8 of the estrous cycle in 3 sheep. Progesterone levels in the utero-ovarian vein and femoral artery had fallen within 6 h to less than 50% of the concentrations seen before injection of the analogue. Luteolysis was not associated with endogenous production of PGF. The concentration of PGF in the uteroovarian vein began to increase 27-39 h after the administration of Estrumate, reaching a mean maximum concentration of 1455pg/ml 48 h after Estrumate. The mean concentration of PGF in the utero-ovarian vein between 36-69 h after Estrumate was significantly greater than during the 24 h before Estrumate (control period) or during the 0-30 h immediately after injection (both P less than 0.001). The maximum secretion of estradiol and the pre-ovulatory LH peak occurred during the period of elevated PGF concentrations in the utero-ovarian veins. The possible importance of endogenous PGF production at this time is discussed.
mesh_terms: D000818:Animals; D003338:Corpus Luteum / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000187:drug effects; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood; D003341:Luteolysis / Q000187:drug effects*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011453:Prostaglandins / Q000494:pharmacology*; D011460:Prostaglandins F / Q000096:biosynthesis*; D012756:Sheep; D013997:Time Factors
chemical_list: D011453:Prostaglandins; D011460:Prostaglandins F; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone