Disaccharidase activity in rat cecum and colon with hyperplasia induced by maltitol or glucomannan

The existence of disaccharidases and an enzyme that hydrolyzes maltitol were investigated in the large intestine of rats. In addition, the properties of disaccharidases were studied in the cecum and colon with hyperplasia induced by the ingestion of nondigestible carbohydrates such as maltitol and glucomannan. Maltase activity was detected in the cecal and colonic mucosa of rats fed a regular diet, although it was a very low level as compared with that in the small intestinal mucosa. Maltitol hydrolysis was notably lower in the cecum and colon than in the small intestine. The Km of maltose was 5.56 mM in the small intestine and 5.59 mM in the cecum, while that in the colon was 2.56 mM. The Vmax of maltose was at very low levels in the cecum (0.38 mumol/mg protein/h) and colon (0.37 mumol/mg protein/h) in comparison with that in the small intestine (30.3 mumol/mg protein/h). With regard to the maltitol hydrolyzing enzyme, Km and Vmax were 2.00 mM and 2.51 mumol/mg protein/h in the small intestine, respectively. Km and Vmax in the cecum and colon could not be measured because the level was too low. The tissue weights of the cecum and colon increased significantly in both the maltitol (p < 0.01, p < 0.05) and glucomannan (p < 0.01, p < 0.05) groups in comparison with that of the control group. The specific activity of maltase decreased significantly in the small intestine of the maltitol (p < 0.05) and glucomannan (p < 0.01) groups. However, maltase activity in the cecum and colon was not lowered by maltitol ingestion, although it decreased significantly in the cecum of the glucomannan group (p < 0.01). Sucrase activity in the small intestine and cecum was decreased significantly by maltitol (p < 0.05, p < 0.01) or glucomannan (p < 0.01, p < 0.01) ingestion, whereas it was not decreased in the colon. Maltitol hydrolyzing activity did not decrease significantly in the small intestine of the maltitol group, although that in the cecum and colon was not measured exactly by the methods used here. These results demonstrate that disaccharidases exist in the cecal and colonic mucosa of rat, and that they are not induced even in the tissue with hyperplasia, which is caused by maltitol ingestion.