ABSTRACT
Background: The presence of food in the intestinal lumen increases absorption from an isolated intestinal loop, the mechanisms involved are unknown. Casein, and its respective hydrolysate, increased D-xylose absorption in both normal volunteers and experimental animals; this effect was associated with prolonged small intestinal transit time and a decrease of motor activity. Aims: To separate from casein hydrolysate, groups of peptides and to investigate their effects on both D-xylose absorption and small intestinal motility. Material and methods: Studies were performed on five dogs with a surgically implanted duodenal cannula. Three groups of peptides were separated by means of a Silica Gel 60 column and were continously infused through the duodenal cannula. After 15 min, 5 g of D-xylose were injected in the duodenum, plasma levels were measured, and the area under the curve was estimated. Motility was recorded by means of infused catheters and external transducers. Results: Plasma levels of D-xylose were significantly increased during the infusion of one group of peptides compared to the others. In addition, the area under the curve: 3366 ñ 885 mg x min-1 observed with this group was significantly greater than the other two groups: 1432 ñ 183 mg x min-1 and 1137 ñ 280 mg x min-1 respectively. No statistically significant differences in motor activity were observed between the different groups of peptides. Conclusions: A group of peptides derived from casein was characterized by increasing D-xylose absorption. The presence of beta casomorphines might be the possible mechanism involved