[Histological and histochemical studies of the stickleback Gasterosteus aculeatus L. kidney. III. Activity of various...

1. The activity of alkaline phosphatase is intensely positive in proximal tubule I and II during the breeding season. In the kidney of secretion producing the enzyme is detectable as against to kidney of winter on the whole proximal tubule II. 2. In the kidney what is able to build a nest, concentration and size of acid phosphatase granules are very increasing in proximal tubule II. 3. The detection of unspecific esterase was negatively already. 4, The reaction of glucose-6-phosphatase is slightly demonstrable in cells of proximal segment of secretion producing what are enlarged fourfold. 5; From the varied reaction of acid and alkaline phosphatase we conclude that both are to set in relation to excretory activity, but not to process of synthesis in kidney of late-spring fish.