Autoradiographic localization of beta-adrenoceptor subtypes in guinea-pig kidney.
The distribution of beta-adrenoceptor subtypes in slide-mounted sections of guinea-pig kidney has been examined by the technique of in vitro labelling combined with autoradiography. Binding of (-)-[125I]-cyanopindolol (Cyp) to kidney sections equilibrated and dissociated slowly, was saturable and stereoselective with respect to the isomers of propranolol and pindolol. These characteristics were appropriate for binding to beta-adrenoceptors. Delineation of beta-adrenoceptor subtypes was achieved by use of betaxolol (beta 1-adrenoceptors) and ICI 118,551 (beta 2-adrenoceptors) and computer assisted curve fitting techniques. Both beta 1- and beta 2-adrenoceptors were present in the proportions 1:2. 3H-Ultrofilm images of (-)-[125I]-Cyp binding to guinea-pig kidney sections showed localized patches of binding in the cortex and concentrated binding in the outer stripe of the medulla. Cortical receptors were of the beta 1 subtype and those associated with the outer stripe of the medulla were of the beta 2-adrenoceptor subtype. beta 1-Adrenoceptors were concentrated over glomeruli and beta 2-adrenoceptors over the straight portion of the proximal tubule.
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D000818:Animals; D001345:Autoradiography; D015784:Betaxolol; D001667:Binding, Competitive; D005260:Female; D006168:Guinea Pigs; D020120:Iodocyanopindolol; D007668:Kidney / Q000378:metabolism*; D007672:Kidney Cortex / Q000378:metabolism; D007678:Kidney Glomerulus / Q000378:metabolism; D007679:Kidney Medulla / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism; D008297:Male; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011412:Propanolamines / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013237:Stereoisomerism; D014018:Tissue Distribution
D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; D020120:Iodocyanopindolol; D010869:Pindolol; D015784:Betaxolol