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

Specific high affinity binding sites for [125I]‐angiotensin II have been identified in crude basolateral and brush border membranes from rat renal cortex. A central high affinity site, KD 0.62 nM; Bmax 299 fmol/mg was identified as part of a complex multicomponent binding system. 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. 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. 1983 British Pharmacological Society