ACTIVITY OF (NA+K+)-STIMULATED ADENOSINTRIPHOSPHATASE IN RAT NEPHRON

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. © 1969 Springer-Verlag.