Levels of Serum Protein Fractions in Diabetic Patients with Retinitis proliferans. ∗

Summary

1. The serum protein-bound carbohydrates and the serum protein fractions were studied in diabetic patients with retinitis proliferans. The serum protein-bound carbohydrates were found to be present in a higher concentration than in non-diabetes. By the method of paper electrophoresis, a definite decrease in the values for the albumin + α₁-globulin fraction and an increase in the α₂-globulin fraction was also found in all of the diabetics, although only those with both retinitis proliferans and proteinuria showed a decrease in the total protein. In the β-globulins no essential change was seen. In the group showing both retinitis proliferans and nephropathy, the γ-globulin concentration tended to be lower than in the group with retinitis proliferans alone, but none of the groups had values distinctly different from those of non-diabetics. 2. It is concluded that disturbances in the protein pattern exist which particularly involve the albumin and α₂-globulin fractions at a stage in the development of the diabetic vascular lesions where the changes cannot be accounted for by loss of protein in the urine.