STREPTOZOTOCIN-INDUCED DIABETES LOWERS RETINOL-BINDING PROTEIN AND TRANSTHYRETIN CONCENTRATIONS IN RATS

Retinol-binding protein (RBP) and transthyretin (TTR) in the plasma, l iver and kidney, retinol in plasma, and total vitamin A in the liver w ere measured in rats 6 weeks after diabetes mellitus had been induced by streptozotocin (STZ). The diabetic rats gained 83% less weight desp ite consuming 45% more feed than the non-diabetic controls. Plasma and kidney concentrations of RBP and TTR were significantly lower in diab etic than in the non-diabetic control rats. Unlike the retinol carrier proteins, plasma albumin concentrations remained unaffected. Plasma c oncentrations of retinol were decreased while its hepatic levels incre ased in the diabetic animals. The depressed circulatory levels of reti nol may reflect an altered metabolism of its transport proteins.