Chronic Depression of Serum Sialic Acid Levels in Alloxan-induced Diabetes

This study was performed to determine whether alloxan treatment of rats alters levels of the terminal carbohydrate residues L-fucose and sialic acid of serum glycoproteins. Results indicate that in the uncompensated diabetic animal a chronic depression of serum sialic acid level occurs with no apparent alteration in the level of L-fucose. The depression in sialic acid level may be attributed in part to decreased activities of hepatic enzymes involved in sialic acid synthesis similar to those observed by others after treatment of rats with the diabetogenic agent streptozotocin. The lack of any significant alteration in the level of L-fucose fails to confirm, in the experimental diabetic animal, the increased protein-bound fucose levels reported in human diabetics. Administration of insulin was not effective in modifying the sialic acid response after alloxan treatment.