Relationship of endogenous to dietary sorbitol. A study in normal and diabetic rats

The relationship of endogenous to dietary sorbitol was investigated by measuring the sorbitol content of plasma, lens and kidney in normal an streptozotocin-injected rats fed for two-three weeks a control diet or a diet rich in either sorbitol or sucrose. The insulin content and secretory capacity of the pancreatic islets removed from these rats was also measured. In normal rats, the carbohydrate-rich diet increased the concentration of sorbitol in plasma but not lens or kidney. The carbohydrate-rich diet also increased the secretory responsiveness of the B-cell to glucose. Accumulation of sorbitol in lens and kidney occurred in diabetic rats. When the diabetic rats were treated with insulin, the sorbitol content of plasma and lens was less elevated than in untreated diabetic animals, despite poor control of the glycemia. The insulin treatment failed to prevent sorbitol accumulation in the kidney. There was no obvious difference between dietary sorbitol and sucrose respectively, in terms of sorbitol accumulation in tissues or stimulation of B-cell secretory potential.