MECHANISMS FOR REGULATION OF CELL VOLUME WITH PARTICULAR REFERENCE TO LENS

From an analysis of the total cation and mobile anion content of the lens it seems likely that there are at least 100 mm of fixed negative charges within the lens. As a result of this distribution, the internal osmolarity would tend to exceed that of the aqueous humor causing the lens to swell. A theoretical explanation, based on membrane flux equations, is given for the maintenance of a constant volume in the normal lens. The normal steady state is achieved by sodium and potassium pumps so linked that one sodium ion is actively extruded for every potassium ion pumped in. It is also demonstrated that by inhibiting the pumps, or by increasing the passive permeability of the lens membranes to sodium, the sodium, chloride and water content of the lens must increase. © 1969.