Kidney Phosphatase

Abstract

The inorganic phosphate, and to a less degree, the acid-soluble organic P in rabbit''s kidney remain constant during adult life. During autolysis of whole kidney, the rate of production of inorganic phosphate is increased by mechanical injury to the organ. Kidney extracts contain an active phosphatase (optimum p H 8.8-9.2). A method has been worked out for estimating approximately the phosphatase content of a tissue extract. Bone phosphatase is correlated with bone growth, kidney phosphatase with functional activity and not with growth of the organ. More phosphatase is present in the cortex than in the medulla. Details are given of the action of kidney phosphatase on several naturally-occurring organic P compounds. Both blood plasma and red cells contain a substrate for kidney phosphatase. Kidney phosphatases from different animals vary in ability to hydrolyse the organic phosphoric esters of the blood. If added to whole blood, however, kidney phosphatase will hydrolyse the organic acid-soluble P in the plasma, but not that in the red cells. Possible physiological significance of kidney phosphatase is discussed. A weak lecithinase, with an optimum p H of 7.0-7.4, is present in the kidney.