[Circadian changes of various enzyme activities in the kidney macula densa of gerbils (Meriones unguiculati)].

Circadian Changes of the Activity of some Enzymes in the Macula densa of the Kidney of Mongolian Gerbilis.--The authors investigated the enzyme histochemical activity of some dehydrogenases in the macula densa of desert rodents killed respectively at 11 a.m. and at 11 p.m. The percentage of macula cells which, in comparison with the non specific distal convolution epithelial cells, showed the same or even enhanced enzyme activities was higher at 11 p. m., i.e. nightly (see Tab. 1).