THE DIURETIC AND NATRURETIC ACTIVITY OF TRIAMTERENE AND SEVERAL RELATED PTERIDINES IN THE RAT

¹ Research and Development Division, Smith Kline & French Laboratories, Philadelphia, Pennsylvania

Diuretic activities of three pteridines, including triamterene (SK&F 8542), in the rat are described. Each produced marked diuretic effects in the sodium-loaded rat, the sodium-deficient rat and in the adrenalectomized rat receiving aldosterone. All three compounds produced marked increases in the excretion of sodium; two of them, SK&F 371 and SK&F 8542 (triamterene), reduce the excretion of potassium at natruretic doses. It is suggested that trimterene acts directly upon a renal port system for sodium which is probably distal and includes the system involved in the exchange of sodium for potassium. While the site of action of triamterene may be in the same portion of the nephron as that affected by aldosterone, the pteridine has been reported to be capable of exerting its effects in the absence of adrenal steroids.