STRAIN VARIATION IN VITAMIN-A (RETINOL) STATUS OF STREPTOZOTOCIN-INDUCED DIABETIC RATS

Decreased plasma concentrations of vitamin A (retinol) and retinol-bin ding protein have been previously identified in human subjects with ty pe I diabetes mellitus. The present study was undertaken to investigat e the effects of streptozotocin-induced diabetes in rats of three diff erent strains including Wistar Furth, Sprague Dawley and Wistar; on pl asma and liver concentrations of vitamin A. The diabetic animals gaine d less weight than nondiabetic control even though they ate 50% more f ood. The hepatic vitamin A concentration was increased at three weeks after the onset of diabetes in all three strains of rats but the magni tude of increase was greater in Wistar than either Wistar Furth or Spr ague Dawley rats. This increased storage of vitamin A in diabetic anim als most likely is due to increased food intake. The plasma concentrat ions of vitamin A, on the other hand, remained unaffected in Wistar Fu rth and decreased moderately (P < 0.02) in Sprague Dawley but severely (P < 0.0001) in Wistar rats. The fact that the plasma vitamin A level s in diabetic Wistar and Sprague Dawley rats were markedly reduced des pite their increased hepatic store suggest an impairment in the transp ort of vitamin A from the liver. The circulatory levels of vitamin A i n Wistar rats are more sensitive to the diabetic state, which is in ag reement with those observations seen in diabetic patients. Because of this similarity, it is reasonable to suggest that Wistar should be the choice of rat strain for future experimental studies involving vitami n A and diabetes relationships.