title: High-performance liquid chromatographic analysis of 'specifically bound' label after [125I]angiotensin II binding to rat brain membranes.
abstract: The combined hypothalamus-thalamus-septum and anteroventral third ventricular region (HTSA) of the rat was examined for [125I]angiotensin II ([125I]AII) binding using two protocols: one that preserved synaptosomal structure and a second that did not. Although maximum binding (Bmax) and dissociation constants (Kd) were similar in both preparations, high-performance liquid chromatographic analyses revealed that [125I]AII made up the majority of specifically bound label in the synaptosome preserved preparation while [125I]tyrosine ([125I]Tyr) represented most of the specifically bound label in the disrupted preparation. These results indicate that [125I]Tyr accumulation occurred subsequent to binding and degradation of [125I]AII and are consistent with the notion that rapid internalization of the receptor-[125I]AII complex occurs in those preparations where the synaptosomal structure remains intact.
mesh_terms: D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002552:Cerebral Ventricles / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012688:Septum Pellucidum / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism
chemical_list: D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D000804:Angiotensin II