Renal actions of azosemide. 2. Micropuncture investigations in rats.

2-Chloro-5-(1H-tetrazol-5-yl)-4-[(2-thienylmethyl)amino]benzene sulfonamide (azosemide) has a potent diuretic and natriuretic action in rats. It was possible to show by micropuncture techniques that azosemide, like furosemide, reduced the fluid and electrolyte reabsorption in the loop of Henle, whilst no diuretic effect was demonstrable in the proximal convoluted tubule. As the sodium and chloride concentrations in the early distal tubular fluid clearly rise, it is assumed that azosemide inhibits the reabsorption of sodium and chloride in the ascending limb of the loop of Henle.