Blood-ocular and blood-brain barrier function in streptozocin-induced diabetes in rats

Edetic acid labeled with chromium 51 was injected intravenously in normal rats and in rats with streptozocin-induced diabetes. One hour after the injection the animals were killed and the concentrations of edetic acid 51Cr in vitreous body, retina, and brain were determined. No significant difference was observed between the two groups for either tissue. In a second series, a mixture of tritiated 1-glucose and aminohippuric acid tagged with carbon 14 was injected instead of edetic acid. A substantial accumulation of aminohippuric acid 14C compared with tritiated 1-glucose was observed in the vitreous body and the brain of diabetic rats in comparison with the control group. It is concluded that untreated streptozocin-induced diabetes in rats for one to two weeks will not cause a generalized increase in the permeability of the blood-ocular or the blood-brain barriers, but organic acids may accumulate in the vitreous body as well as in the brain as a consequence of reduced outward transport through these barriers.