title: Identification of beta-adrenoceptor subtypes in bovine ovarian and myometrial cell membranes.
abstract: Beta-adrenoceptor (beta-AR) concentrations were measured in the ovary and in the myometrium of 36 adult Friesian cows using a radiometric assay. The beta-AR content in both tissues was determined using the highly specific antagonist (-) [3H]CGP 12177 and the amounts of beta-AR subtypes were discriminated in the presence of highly selective unlabelled ligands (CGP 20712A, ICI 118 551, CGP 25827A). Scatchard analysis revealed a good linearity and Kd values suggested the existence of high affinity beta-adrenergic sites in the bovine genital tract. Total beta-AR concentrations in the ovary and in the myometrium were, respectively, 87 +/- 7 (SEM) and 240 +/- 27 fmol mg-1 of membrane protein. beta 2-AR concentrations were significantly higher (P < 0.01) in the ovary (66 +/- 5) and the myometrium (180 +/- 29) than those of beta 1-AR (21 +/- 4 and 60 +/- 5, respectively). Significant differences (P < 0.05) were also to be found between high affinity state beta 2-AR and low affinity beta 2-AR concentrations, but their values correlated negatively in the two different tissues. Natural and synthetic agonists inhibited (-) [3H]CGP 12177 binding to beta-AR in the following order of potency: (-)isoproterenol > (+/-)clenbuterol > or = (-)adrenaline >> >> (-)noradrenaline, whereas synthetic antagonists inhibited binding in the following order of potency: (-)propranolol >> (+/-)ICI 118 551 >> >> (+/-)CGP 20712A.
authors.affiliation: Department of Animal Pathology, University of Turin, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Re
authors.forename: P
authors.initials: P
authors.lastname: Badino
authors.forename: A
authors.initials: A
authors.lastname: Novelli
authors.forename: M G
authors.initials: MG
authors.lastname: Canese
authors.forename: C
authors.initials: C
authors.lastname: Girardi
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry; D005260:Female; D009215:Myometrium / Q000737:chemistry*; D010053:Ovary / Q000737:chemistry*; D011869:Radioligand Assay; D018342:Receptors, Adrenergic, beta-1 / Q000032:analysis*; D018343:Receptors, Adrenergic, beta-2 / Q000032:analysis*
chemical_list: D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2