Sorbitol Pathway Metabolites in the Diabetic Rabbit Lens

The lenses of diabetic rabbits with an average plasma glucose of 502 ± 119 mg. per 100 ml. have 141 ± 44 mg. per 100 Gin. glucose, 81 ± 37 sorbitol, and 94±12 fructose. For a comparable level of lens glucose, the values for sorbitol and fructose in the diabetic rabbit lens are, respectively, one tenth and one half of the values found in the diabetic rat lens. This difference appears to depend primarily on relative deficiencies of TPNH and DPN in the rabbit lens, such deficiencies being enhanced by diabetes. Incubations of lens homogenates indicate a sluggish sorbitol pathway in the rabbit but such homogenates may not furnish the best evidence. Rabbit lenses develop peripheral vacuoles at much lower sorbitol levels than rat lenses, suggesting that in the diabetic rabbit lens a metabolic disturbance may be more important than osmotic effects.