EFFECTS OF DIABETES AND HYPERGLYCEMIA ON DISACCHARIDASE ACTIVITIES INTHE RAT

Background and Methods: To elucidate the effect of hyperglycemia on di saccharidase activities, the specific and total activities of the disa ccharidases were measured in the intestinal mucosa and kidney cortex o f diabetic and hyperglycemic rats. The diabetes was induced with an in traperitoneal injection of streptozotocin (60 mg/kg). The rats were ma de hyperglycemic with an intravenous instillation of a solution contai ning 40% dextrose monohydrate at a rate of 1.5 ml/h for 24 h. Results: The blood glucose level was 387 +/- 45 mg/dl and 382 +/- 35 mg/dl (me an +/- standard deviation) in diabetic and hyperglycemic rats, respect ively. In diabetic rats the intestinal maltase, sucrase, and lactase a ctivities were significantly higher than those in control rats. Simila rly, disaccharidase activities in hyperglycemic rats were significantl y higher than those in control rats. The renal maltase activity in dia betic rats was significantly lower than that in control rats. The malt ase activity in hyperglycemic rats, however, was not significantly dif ferent from that in control rats. Conclusions: These results suggest t hat 1) hyperglycemia directly increases the activities of intestinal m altase, sucrase, and lactase; 2) hyperglycemia does not influence rena l maltase activity; and 3) hyperglycemia is partly responsible for inc reased activities of intestinal disaccharidases in diabetes mellitus.