The influence of hardly digestive starch granules on sucrase and isomaltase in small intestinal mucosa of rats.

Abstract

SummaryThe effects of potato-starch granules (PSG) on sucrase and isomaltase activities in the small intestinal mucosa of rats were examined by gel filtration on a Sephacryl S-300 column . Young and adult rats were administered the diet containing 50% of either PSG or pregelatinized potato starch (PPS) as a control for 7days. Mucosal homogenates were prepared from the small intestine and separated into their component disaccharidases on the column. The sucrase activity , increased by feeding young rats on the PSG diet, was detected in the sucrase-Isomaltase complex by changing the activity ratio of the two enzymes . In adult rats, however, the complex seemed to be mature and the increased sucrase moiety was newly combined with a free isomaltase moiety and comprised a portion of the complex. These changes were observed not only in soluble disaccharidases but also in membrane-bound ones . Furthermore, there was a remarkable change of sucrase activity in the distal portion of the small intestine rather than in the proximal .