Separan AP-273 and renal function: a novel natriuretic substance

Recent studies have demonstrated that an anionic polyacrylamide (Separan, Union Carbide Corp.) decreased the formation of atherosclerotic lesions in the rabbit (Separan AP-30) and increased cardiac output (Separan AP-273) in the rat. Since the effect of these compounds on renal function was unknown, we investigated the dose-response relationship between Separan AP-273 and the renal excretion of electrolytes and water. In the anesthetized rat, intravenous injections of Separan at 0.01, 0.03, 0,10, and 0.30 mg/kg produced a dose-related increase in urine volume, sodium excretion, and osmolar clearance. Potassium excretion was increased less than twofold only at the maximal dose tested. At this high dose, the effect on sodium and water excretion was greater (five- and seven-fold, respectively). Creatinine clearance was not altered by these interventions. As well, the maximal dose studied was previously shown to have no effect on blood flow. These results indicate that Separan AP-273 is a potent diuretic and natriuretic substance. Taken together with similar studies using the poly(ethylene oxide) Polyox WSR N-60K, these results suggest that drag-reducing polymers may represent a novel group of compounds with diuretic and natriuretic effects.