Lens Metabolism as Studied with the Reversible Cation Shift: III. The Effect of Lens Age (Size)

There is evidence to suggest that the response of the lens to certain physiologic or metabolic stresses varies with the lens age. The observation is of more than passing interest. The immediate importance of such information concerns its application to various in vivo and in vitro experimental situations. The ultimate value would conceivably stem from the application of such studies to an understanding of the senile process, specifically the senile cataract. Important among these observations are the following:First, the age of the lens influences its response in vitro to the physiologic stress induced by cold. If the isolated rabbit lens is refrigerated at 0 C, it loses potassium and gains sodium and water; when subsequently incubated at 37 C, the sodium is excreted from the lens and the potassium reenters the lens, the movement of both cations being against a concentration gradient. This migration of cations against a gradient