Influence of streptozotocin- and alloxan-induced diabetes on the metabolism of glycosaminoglycans

Abstract

GAG metabolism was investigated in rats with experimentally induced diabetes. In comparison to control animals, the uptake of 35S-sulfate was diminished in tissues of diabetic animals. Streptozotocin-induced diabetes showed a significant decrease in the content of GAG fractions except that of non-sulfated GAG in liver and kidney which was unchanged as compared to the control group. In rats rendered diabetic by alloxan, non-sulfated GAG increased appreciably in liver and kidney whereas highly sulfated GAG remained unchanged. In the skins of alloxan-diabetic rats both total and sulfated GAG decreased significantly. The activities of liver beta-glucuronidase, beta-N-acetyl glucosaminidase and cathepsin D were significantly increased in rats treated with streptozotocin and alloxan. In streptozotocin-diabetic rats, renal beta-glucuronidase and beta-N-acetyl glucosaminidase activities were reduced while cathepsin D activity was similar to that of controls. The renal beta-N-acetyl glucosaminidase and cathepsin D activities of alloxan-treated rats were not significantly different from normal but their beta-glucuronidase was significantly increased. In the spleen of streptozotocin-diabetic rats all the enzymes were increased except beta-N-acetyl glucosaminidase which remained unaltered. Increased excretion of uronic acid was observed in diabetic groups. These results collectively indicate that both streptozotocin- and alloxan-induced diabetes altered the synthesis and catabolism of GAG.