title: Uterine oxytocin receptors in an Australian marsupial, the brushtail possum, Trichosurus vulpecula.
abstract: 1. Oxytocin receptors in the uterus of the brushtail possum (T. vulpecula) were characterized by radioreceptor assay and compared with those of the sheep and rat uterus. 2. A single oxytocin binding site was found with an affinity (Kd) and receptor concentration (Ro) of 3.0 +/- 0.8 nmol/l and 200 +/- 60 fmol/mg protein, respectively (SEM; n = 5). The receptor was stable at -20 degrees C; divalent ions were required for optimum binding. 3. Competitive displacement curves with related peptides showed the following order of specificity: vasotocin greater than oxytocin greater than mesotocin = arginine-vasopressin = [Thr4, Gly7]-oxytocin greater than lysine-vasopressin = isotocin much greater than [d(CH2)5, D-Phe2, Ile4, Ala9-NH2]-AVP. 4. It was concluded that oxytocin receptors in the possum have similar characteristics to those of placental mammals.
authors.affiliation: Department of Physiology and Pharmacology, University of Queensland, St. Lucia, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Sernia
authors.forename: J
authors.initials: J
authors.lastname: Garcia-Aragon
authors.forename: W G
authors.initials: WG
authors.lastname: Thomas
authors.forename: R T
authors.initials: RT
authors.lastname: Gemmell
mesh_terms: D000818:Animals; D001315:Australia; D005260:Female; D009893:Opossums / Q000502:physiology*; D010121:Oxytocin / Q000032:analysis*; D011869:Radioligand Assay; D051381:Rats; D011945:Receptors, Angiotensin / Q000032:analysis*; D018045:Receptors, Oxytocin; D012756:Sheep; D013045:Species Specificity; D014599:Uterus / Q000032:analysis*
chemical_list: D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin; D010121:Oxytocin