Enzymatic glycosidase activities in experimental obesity

Glycosidases are lysosomal enzymes that participate in the catabolism of glycoproteins and other glycoconjugates, and in some way may modify their activity in situations in which carbohydrate metabolism could be altered, such as the case of obesity. Using a fluorometric assay, a study was made of four glycosidase activities: N-acetyl-beta-D-hexosaminidase (NAG), alpha-mannosidase and alpha- and beta-glucosidase in the serum, pancreas, liver and kidney of 22 Zucker fa/fa genetically obese rats and of 23 fa/? controls, both with ages ranging between 13 and 15 weeks. After 12-14 hours fast and prior anaesthesia with sodium pentobarbital intraperitoneally, blood and the afore-mentioned organs were removed for enzymatic study of the serum and the organs after homogenization and centrifugation. In the serum a statistically significant increase in alpha-mannosidase (p < 0.0001) and alpha-glucosidase (p < 0.02) activities was found in the fa/fa obese rats as compared with the controls. No statistically significant differences were found in serum hexosaminidase activity between the two groups, and no serum beta-glucosidase enzymatic activity was detected. In liver, a decrease was observed in hexosaminidase (p < 0.002) and alpha-glucosidase (p < 0.01) activities in the obese rats as compared with the controls. In whole pancreas an increase was found in alpha-glucosidase activity in the obese rats with respect to the controls (p < 0.001), with no statistically significant differences in the hexosaminidase, alpha-mannosidase and beta-glucosidase activities.(ABSTRACT TRUNCATED AT 250 WORDS)