Identification of β-adrenoceptor subtypes in bovine ovarian and myometrial cell membranes

Beta-adrenoceptor (β-AR) concentrations were measured in the ovary and in the myometrium of 36 adult Friesian cows using a radiometric assay. The β-AR content in both tissues was determined using the highly specific antagonist (−) [ 3H]CGP 12177 and the amounts of β-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 K d values suggested the existence of high affinity β-adrenergic sites in the bovine genital tract. Total β-AR concentrations in the ovary and in the myometrium were, respectively, 87 ± 7 ( sem) and 240 ± 27 fmol mg −1 of membrane protein. β 2-AR concentrations were significantly higher ( P