Osmotic Changes caused by the Accumulation of Dulcitol in the Lenses of Rats fed with Galactose

Abstract

CATARACTS produced experimentally in rats maintained on a diet high in galactose or xylose or by alloxan injection have similar clinical manifestations¹. Since the development and appearance of these cataracts are similar, there is the suggestion that a common mechanism or factor may be involved. We wondered whether the accumulation of polyols first observed by van Heyningen^2,3 might possibly be the initiating factor in these cataracts. It seemed possible that the accumulation of polyols, along with the keto sugars, in the lens fibres might be sufficient to create an osmotic disturbance. Because of the increase in the osmotically active substances, water would be drawn into the lens fibres. Since sugars, especially the sugar alcohols, do not readily diffuse through biological membranes, their concentrations might reach a level which would increase the volume of water sufficiently to cause the lens fibres to swell and perhaps to rupture their membranes.