LACTOSE LOAD ENHANCES THE GROWTH OF THE SMALL-INTESTINE IN RATS

The present study was undertaken to elucidate the controversial issue regarding the small intestinal structural adaptation, in lactose fed r ats. Three study groups were used. One experimental fed 60% lactose an d two controls in which the lactose was substituted for similar amount of starch. One of them was fed ad libitum and another a limited amoun t of food to match the body weight of lactose group. The weight, lengt h of the intestine and intestinal mucosal DNA and protein were determi ned at days 2, 5, 10 and 30 of the experiment. As compared to starch f ed ad libitum controls, animals fed 60% lactose diet ate similar amoun t of food, grew at a slower rate and weighed 16,7% less at the end of the experiment. In contrast to retarded gain in body weight, small int estinal mucosa of these animals contained more DNA (22,5%) and protein (37,5%) than that of controls. These changes were paralleled by incre ase in length (17%) and weight of the intestine (24,2%). Therefore, th e results of the present study confirmed the findings that the small i ntestine increases in size in response to lactose feeding and that thi s occurs in the abscense of hyperphagia. It was further demonstrated t hat this increase was due both to mucosal cell hyperplasia and hypertr ophy.