Renal effects of synthetic rat-atrial natriuretic peptide in nephron-reduced rats with nephrotoxic nephritis.

Following nephron reduction by means of five--sixths nephrectomy (Nx), nephritis was induced in rats by injection of nephrotoxic serum (NTS). A continuous intravenous infusion of synthetic rat--atrial natriuretic peptide (r-ANP) at 2.5 micrograms/min for produced remarkable diuresis and natriuresis in these rats. Furthermore, inulin clearance, para-amino-hippuric acid clearance and filtration fraction increased in spite of the reduction of mean arterial pressure during the infusion of r-ANP. It was therefore evident that diuresis and natriuresis were mediated by a direct action of r-ANP in the kidney. We observed that r-ANP was a diuretic, natriuretic and hypotensive agent but at a higher dosage in Nx rats with NTN.