title: Prostaglandin E1 or E2 inhibits an oxytocin-induced premature luteolysis in ewes when oxytocin is given early in the estrous cycle.
abstract: The objective of this study was to determine whether PGE1 or PGE2 prevents a premature luteolysis when oxytocin is given on Days 1 to 6 of the ovine estrous cycle. Oxytocin given into the jugular vein every 8 hours on Days 1 to 6 postestrus in ewes decreased (P ≤ 0.05) luteal weights on Day 8 postestrus. Plasma progesterone differed (P ≤ 0.05) among the treatment groups; toward the end of the experimental period, concentrations of circulating progesterone in the oxytocin-only treatment group decreased (P ≤ 0.05) when compared with the other treatment groups. Plasma progesterone concentrations in ewes receiving PGE1 or PGE1 + oxytocin were greater (P ≤ 0.05) than in vehicle controls or in ewes receiving PGE2 or PGE2 + oxytocin and was greater (P ≤ 0.05) in all treatment groups receiving PGE1 or PGE2 than in ewes treated only with oxytocin. Chronic intrauterine treatment with PGE1 or PGE2 also prevented (P ≤ 0.05) oxytocin decreases in luteal unoccupied and occupied LH receptors on Day 8 postestrus. Oxytocin given alone on Days 1 to 6 postestrus in ewes advanced (P ≤ 0.05) increases in PGF2α in inferior vena cava or uterine venous blood. PGE1 or PGE2 given alone did not affect (P ≥ 0.05) concentrations of PGF2α in inferior vena cava and uterine venous blood when compared with vehicle controls or oxytocin-induced PGF2α increases (P ≤ 0.05) in inferior vena cava or uterine venous blood. We concluded that PGE1 or PGE2 prevented oxytocin-induced premature luteolysis by preventing a loss of luteal unoccupied and occupied LH receptors.
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Yoshie S
authors.initials: YS
authors.lastname: Weems
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: John
authors.initials: J
authors.lastname: Pang
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Raney
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Tracie
authors.initials: T
authors.lastname: Uchima
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Esther
authors.initials: E
authors.lastname: Lennon
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Drew
authors.initials: D
authors.lastname: Johnson
authors.affiliation: College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Ft. Collins, Colorado, USA.
authors.forename: Torrance M
authors.initials: TM
authors.lastname: Nett
authors.affiliation: Texas AgriLife Research, Texas A&M System, Overton, Texas, USA.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Randel
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA. Electronic address: weems@hawaii.edu.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Weems
mesh_terms: D000527:Alprostadil / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D015232:Dinoprostone / Q000008:administration & dosage / Q000494:pharmacology*; D004971:Estrus / Q000187:drug effects*; D003341:Luteolysis / Q000187:drug effects; D010121:Oxytocin / Q000494:pharmacology*; D011374:Progesterone / Q000097:blood; D012756:Sheep / Q000502:physiology*; D013997:Time Factors
chemical_list: D011374:Progesterone; D010121:Oxytocin; D000527:Alprostadil; D015232:Dinoprostone
keywords: Corpus luteum; Oxytocin; PGE(1); PGE(2); PGF(2α); Progesterone