WAKO, Y., SUZUKI, K., GOTO, Y. and KIMURA, S. Vitamin A Transport in Plasma of Diabetic Patients. Tohoku J. exp. Med., 1986, 149 (2), 133-143-The effects of diabetes on the vitamin A metabolism were studied. The concentrations of plasma retinol and retinyl ester were measured in diabetic patients using high-performance liquid chromatography (HPLC). In diabetic patients, the mean level of retinyl ester was significantly elevated compared to that of normal subjects (diabetes, 68.3±42.5IU/100ml of plasma; study I, 87.6±64.3IU/100ml of plasma; study II vs. normal, 29.8± 10.3IU/100ml of plasma). The ultracentrifugal and column chromatographic studies were carried out to examine the distribution of retinyl ester in patient's plasma. Ultracentrifugation study showed that the mean of 72.6% of retinyl ester was recovered in the lipoproteins of density higher than 1.006 and the remainder was recovered in the chylomicron (d<1.006). Gel filtration profiles for the separation of plasma vitamin A demonstrated that retinyl ester presented in the HDL, LDL and larger molecular size lipoprotein (suspected to be VLDL) as well as in the chylomicron.