The sorbitol shunt in the retina and the optic nerve of mice with inherited and STZ-induced diabetes.

Micromethods designed for studying the sorbitol shunt permitted studies of the retina and the optic nerve from mice. A significant accumulation of sorbitol was found in the retina of 5-months-old obese-hyper-glycaemic and severely STZ diabetic mice. The latter mice also showed increased sorbitol concentrations in the optic nerve. The activities of aldose reductase were about 3 times higher in the optic nerve than in the retina. Our findings show that not only the retina but also the optic nerve accumulates sorbitol. It is suggested that this hypothetically may lead to degeneration of the optic nerve in severe diabetes as in peripheral nerves.