The binding of [125I]-angiotensin to rat renal epithelial cell membranes

1 Specific high affinity binding sites for [125I]-angiotensin II have been identified in crude basolateral and brush border membranes from rat cortex. 2 A central high affinity site, KD 0.62 nM; Bmax 299 fmol/mg was identified as part of a complex multicomponent binding system. 3 This high affinity site was saturable and exhibited specificity for angiotensin II analogues and closely related peptides but not for bradykinin, substance P or peptide fragments of angiotensin II. 4 Specific [125I]-angiotensin II binding was partially dependent on NaCl. Absence of NaCl resulted in a decrease in Bmax, had no effect on the rate of association but increased the rate of dissociation of [125I]-angiotensin from its binding site.