THE EFFECT OF X‐IRRADIATION ON THE SODIUM‐POTASSIUM‐ACTIVATED ADENOSINE TRIPHOSPHATASE (Na‐K‐ATPase) ACTIVITY IN THE EPITHELIUM OF THE RAT LENS A Histochemical and Biochemical Study

Abstract

Epithelial Na-K-ATPase activity of the rat lens was studied after X-irradiation at intervals of 3-90 days. The enzyme was demonstrated histochemically by light microscopy and it was measured biochemically by a fluorometric method. Neither histochemical nor biochemical changes of Na-K-ATPase content of the lens epithelium were observed during cataract development. In whole-mount preparations the enzyme activity was localized in the cell membranes. After radiation (1 mo.) a few peripheral cells also had a precipitate over the whole cell. Unaltered Na-K-ATPase content in the epithelium suggests that hydration of the lens after X-irradiation is primarily caused by changes in passive permeability properties of the cell membranes and not by a decreased capacity of the active cation pump.