Activity of (Na+K+)-stimulated adenosintriphosphatase in the rat nephron

Summary In 17 male Wistar rats in antidiuresis 10 different nephron segments and arteries are identified with the aid of Lowry's technique, dissected and total-and (Mg⁺⁺)-adenosintriphosphatase (=ATPase) determined. (Na⁺K⁺)-activated ATPase in the distal tubule is four to five times (max. eight times) more active than in the proximal segment. This difference of activity may speak for a high pump mechanism mediated by the way of a (Na⁺K⁺)-activated enzyme system in the distal nephron and for a partially passive reabsorption of sodium from the proximal convolution.With the support of the Schweiz. Nationalfonds zur Förderung der wissenschaftlichen Forschung (Nr. 4256 and Nr. 4809.3)