Specific receptors for atrial natriuretic polypeptide on basolateral membranes isolated from rat renal cortex

The binding of alpha-human atrial natriuretic polypeptide (alpha-hANP) to brush border and basolateral membranes isolated from the rat renal cortex was studied at 0 degree C by a rapid filtration technique. Specific binding of 125I-alpha-hANP to basolateral membranes reached a steady state at 4 hr. The binding to brush border membranes was maximal at 5-15 min and then rapidly decreased. The analysis of incubation mixtures with basolateral membranes revealed little degradation of 125I-alpha-hANP during the 4-hr incubation, while there was extensive degradation of the ligand with brush border membranes during the 30-min incubation. High affinity binding of 125I-alpha-hANP was demonstrated on basolateral membranes but not on brush border membranes. These data suggest that specific receptors for alpha-hANP are localized on basolateral membranes of the renal cortex.