title: Effects of indomethacin, luteinizing hormone (LH), prostaglandin E2 (PGE2), trilostane, mifepristone, ethamoxytriphetol (MER-25) on secretion of prostaglandin E (PGE), prostaglandin F2alpha (PGF2alpha) and progesterone by ovine corpora lutea of pregnancy or the estrous cycle.
abstract: Two experiments were conducted to determine the luteotropin of pregnancy in sheep and to examine autocrine and paracrine roles of progesterone and estradiol-17 beta on progesterone secretion by the ovine corpus luteum (CL). Secretion of progesterone per unit mass by day-8 or day-11 CL of the estrous cycle was similar to day-90 CL of pregnancy (P > or = 0.05). In experiment 1, secretion of progesterone in vitro by slices of CL from ewes on day-8 of the estrous cycle was increased (P < or = 0.05) by LH or PGE2. Secretion of progesterone in vitro by CL slices from day-90 pregnant ewes was not affected by LH (P > or = 0.05) while PGE2 increased (P < or = 0.05) secretion of progesterone. Day 8 ovine CL of the estrous cycle did not secrete (P > or = 0.05) detectable quantities of PGF2alpha or PGE while day-90 ovine CL of pregnancy secreted PGE (P < or = 0.05) but not PGF2alpha. Secretion of progesterone and PGE in vitro by day-90 CL of pregnancy was decreased (P < or = 0.05) by indomethacin. The addition of PGE2, but not LH, in combination with indomethacin overcame the decreases in progesterone by indomethacin (P < or = 0.05). In experiment 2, secretion of progesterone in vitro by day-11 CL of the estrous cycle was increased at 4-h (P < or = 0.05) in the absence of treatments. Both day-11 CL of the estrous cycle and day-90 CL of pregnancy secreted detectable quantities of PGE and PGF2alpha (P < or = 0.05). In experiment 1, PGF2alpha secretion by day-8 CL of the estrous cycle and day-90 ovine CL of pregnancy was undetectable, but was detectable in experiment 2 by day-90 CL. Day 90 ovine CL of pregnancy also secreted more PGE than day-11 CL of the estrous cycle (P < or = 0.05), whereas day-8 CL of the estrous cycle did not secrete detectable quantities of PGE (P > or = 0.05). Trilostane, mifepristone, or MER-25 did not affect secretion of progesterone, PGE, or PGF2alpha by day- 11 CL of the estrous cycle or day-90 CL of pregnancy (P > or = 0.05). It is concluded that PGE2, not LH, is the luteotropin at day-90 of pregnancy in sheep and that progesterone does not modify the response to luteotropins. Thus, we found no evidence for an autocrine or paracrine role for progesterone or estradiol-17 36 on luteal secretion of progesterone, PGE or PGF2alpha.
authors: Dept. of Animal Science, University of Hawaii, Honolulu 96822, USA.
authors: L
authors: L
authors: Kim
authors: Y S
authors: YS
authors: Weems
authors: P J
authors: PJ
authors: Bridges
authors: B R
authors: BR
authors: LeaMaster
authors: L
authors: L
authors: Ching
authors: D L
authors: DL
authors: Vincent
authors: C W
authors: CW
authors: Weems
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors; D000818:Animals; D003338:Corpus Luteum / Q000187:drug effects / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000494:pharmacology; D015237:Dinoprost / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000502:physiology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D004971:Estrus; D004978:Ethamoxytriphetol / Q000494:pharmacology; D005260:Female; D006727:Hormone Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000494:pharmacology; D015735:Mifepristone / Q000494:pharmacology; D011247:Pregnancy; D011374:Progesterone / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology*; D011458:Prostaglandins E / Q000378:metabolism*; D012756:Sheep / Q000502:physiology*
chemical_list: D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D004965:Estrogen Antagonists; D006727:Hormone Antagonists; D011458:Prostaglandins E; D013196:Dihydrotestosterone; D015735:Mifepristone; D011374:Progesterone; D004958:Estradiol; D004978:Ethamoxytriphetol; D007986:Luteinizing Hormone; D015237:Dinoprost; D015096:3-Hydroxysteroid Dehydrogenases; D015232:Dinoprostone; C009954:trilostane; D007213:Indomethacin