NATRIURETIC PEPTIDE RECEPTOR-A AND RECEPTOR-B HAVE DIFFERENT CELLULAR-DISTRIBUTIONS IN RAT-KIDNEY

The cellular distribution of guanylyl cyclase coupled natriuretic pept ide receptors type A (GC-A) and type B (GC-B) was examined by immunocy tochemistry in normal rat kidney, and compared with the distribution o f the vacuolar H+-ATPase. Staining for GC-A was found in glomeruli, th in limbs of Henle's loop, cortical collecting tubule, and inner medull ary collecting duct. Staining for GC-B was found in glomeruli and the same nephron sections as GC-A, with the exception of the thin limbs. I n the cortical collecting tubule, GC-A was found in both principal and intercalated cells; GC-B was restricted to the apical pole of alpha i ntercalated cells. In inner medullary collecting ducts cells, GC-A was located on the basal membrane, whereas GC-B was found in the apical p ole. The different pattern of polarization of natriuretic peptide rece ptors in the inner medulla provides a plausible basis for the differen t physiologic effects of atrial natriuretic factor and C-type natriure tic peptide. The results also suggest the possibility that GC-B is inv olved in the regulation of bicarbonate transport in the cortical colle cting tubule.