title: Occurrence of alpha 2-adrenergic effects on adenylate cyclase activity and (3H)-clonidine specific binding in brown adipose tissue from foetal rats.
abstract: Noradrenaline maximally stimulates adenylate cyclase activity in brown adipocytes from foetal rats by 400%. Isoproterenol maximally stimulates the adenylate cyclase activity by 600%. The differences observed in the dose-response curves of adenylate cyclase activity to isoproterenol or noradrenaline were prevented in the presence of clonidine (a alpha 2-agonist) or yohimbine (alpha 2-antagonist) respectively. (3H)-clonidine binds specifically to brown fat membranes saturable (from 1.75 to 20 nM). Scatchard analysis revealed a Bmax of 22 fmol/mg and a KD of 10 nM.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000196:embryology / Q000201:enzymology / Q000378:metabolism*; D000818:Animals; D003000:Clonidine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D015016:Yohimbine / Q000378:metabolism
chemical_list: D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D003000:Clonidine; D009638:Norepinephrine