Rapid method for study of enzyme distribution in rat kidney

¹ Department of Pharmacology, Washington University School of Medicine, Saint Louis, Missouri

A rapid method for localizing enzymatic levels in various structures of the kidney is described. This method consists of dissecting a cone from rapidly frozen kidney, and measuring the enzyme activities of thin slices from the cortex to the papilla. The use of this method in elucidating the distribution of d- and l-amino acid oxidases and of hexokinase and glucose 6-phosphatase in adult rat kidney and of the last two enzymes in young rat kidney from birth to weaning is reported. Glucose 6-phosphatase was most active in the cortex and least active in the papilla in all age groups. The site of maximum glucose 6-phosphatase activity coincides with the alleged site of glucose reabsorption. Hexokinase was highest in the papilla and lowest in the outer cortex in most ages. l- Amino acid oxidase was concentrated in the midcortex, and d-amino acid oxidase in the border between the cortex and medulla.