The effects of sodium salicylate on the metabolism of the retina

Certain aspects of the effects of salicylate on retinal metabolism are considered. In vivo administration of sodium salicylate induces an increase in the absolute level of lactic acid in the retina. Such treatment is also shown to result in a slight stimulatory effect on lactic acid production by the subsequently excised retina, but to have no significant effect on the rate of glucose uptake. Incubation of the normal retina, with or without salicylate, reveals that under aerobic conditions both glucose uptake and lactic acid production are stimulated; 2,4 dinitrophenol imitates this effect. Under anaerobic conditions, both these activities are inhibited. There is no apparent effect of salicylate on total lactic acid dehydrogenase activity or on the isoenzyme pattern. It is concluded that the beneficial effects of salicylates on diabetic retinopathy cannot be explained in terms of a lowering of lactic acid concentration, as has been suggested. The significance of the increased uptake of glucose is discussed.