Enzyme Activity in the Nephron: Quantitative Study by Ultramicrochemical Techniques

The many new techniques developed in the past few decades have provided the impetus to the increasingly detailed consideration of the biology of the cell as a structural and functional unit.¹ As a result of the dissection studies of Oliver,^2,3 the recent application of electronmicroscopy to the study of the structure of the kidney^4,5 and the elegant observations on the composition of the fluid of individual tubules initiated by Richards,⁶ Gottschalk,⁷ Wirz⁸, and Ullrich,⁹ it is now possible to study the kidney in terms of its individual structural and functional units, the nephrons, under varying physiologic conditions. The direct measurements which are being made by these techniques are beginning to provide objective data to illuminate structural and functional aspects of the nephron.

Enzymes are probably involved as catalysts in many of the mechanisms underlying the physiological processes of reabsorption from and secretion into the