title: Oxytocin-stimulated inositol phosphate turnover in endometrium of ewes is influenced by stage of the estrous cycle, pregnancy, and intrauterine infusion of ovine conceptus secretory proteins.
abstract: Three experiments (Exp) assessed the influence of stage of the estrous cycle, pregnancy, and intrauterine infusion of ovine conceptus secretory proteins (oCSP) on turnover of inositol trisphosphate (the putative second-messenger for oxytocin-stimulated secretion of prostaglandin F2 alpha) in ovine endometrium during luteolysis and maternal recognition of pregnancy. In Exp 1, endometrium was collected from 5 cyclic (Cy) and 6 pregnant (P) ewes on Day 16 after onset of estrus. In Exp 2, endometrium was collected from Day 12 Cy (n = 5), Day 12 P (n = 3), Day 16 Cy (n = 4), and Day 16 P (n = 3) ewes. In Exp 3, 12 Cy ewes were allotted randomly, in a 2 x 2 factorial arrangement, to receive serum protein (SP), or oCSP and estradiol-17 beta (E2), or vehicle treatments. Ewes were injected i.v. with 0.5 mg E2 or vehicle on Day 12 and received twice-daily infusions of 1.5 mg SP or oCSP (containing 25 micrograms ovine trophoblast protein-1 by radioimmunoassay [RIA]) + SP (1.5 mg total protein) into each uterine horn on Days 12, 13, and 14. Blood samples for RIA of plasma progesterone were collected on Days 10-15 (before treatment on each day) and endometrium was collected on Day 15. For each Exp, 100 mg endometrium was incubated, in duplicate, for 2 h with 10 microCi [3H] inositol and treated with 0 or 100 nM oxytocin (OT) for 20 min, then [3H]inositol mono-, bis-, and trisphosphates (IP1, IP2, and IP3, respectively) were quantified.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Animal Science Department, University of Florida, Gainesville 32611.
authors.forename: M A
authors.initials: MA
authors.lastname: Mirando
authors.forename: T L
authors.initials: TL
authors.lastname: Ott
authors.forename: J L
authors.initials: JL
authors.lastname: Vallet
authors.forename: M
authors.initials: M
authors.lastname: Davis
authors.forename: F W
authors.initials: FW
authors.lastname: Bazer
mesh_terms: D000818:Animals; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism*; D004971:Estrus / Q000378:metabolism*; D005260:Female; D007294:Inositol / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007370:Interferon Type I; D010121:Oxytocin / Q000494:pharmacology*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D012756:Sheep / Q000378:metabolism*
chemical_list: D007370:Interferon Type I; D011257:Pregnancy Proteins; C020947:interferon tau; D011374:Progesterone; D007294:Inositol; D010121:Oxytocin; D015544:Inositol 1,4,5-Trisphosphate