[Na+--K+-adenosine triphosphatase and some oxidoreductases in the kidney of rats with spontaneous hypertension].

The activities of the Na+--K+-ATPase, succinic dehydrogenase (SDH/, lactic dehydrogenase (LDH/ and glucose-6-phosphat dehydrogenase (G-6-PDH/ were studied in the cortex outer and inner medulla of the kidneys of rats with spontaneous hypertension (SHR) and were compared with those of control normotensive Wistar rats. The SHR aged 6--8 weeks had durint the prehypertensive and the early hypertensive stage the same enzymatic activities as control rats. Rats with a steady SH aged 16-22 weeks had low specific activity of the, Na+--K+-ATPase, SDH and LDH in the outer medulla. The latter can be associated with decreased intensity of the energy metabolism and a reduction of the active sodium transport in the ascending limb of the loop of Henle in the SHR rats and cold cause the phenomenon of exaggerated natriuresis characteristic of hypertension.