EFFECT OF CASEIN DERIVED PEPTIDES ON D-XYLOSE ABSORPTION AND SMALL-INTESTINAL MOTILITY

Background: The presence of food in the intestinal lumen increases abs orption from an isolated intestinal loop, the mechanisms involved are known. Casein, and its respective hydrolysate, increased D-xylose abso rption in both normal volunteers and experimental animals; this effect was associated with prolonged small intestinal transit time and a dec rease of motor activity. Aims: To separate from casein hydrolysate, gr oups of peptides and to investigate their effects on both D-xylose abs orption and small intestinal motility. Material and methods: Studies w ere performed on five dogs with a surgically implanted duodenal cannul a. Three groups of peptides were separated by means of a Silica Gel 60 column and were continuously infused through the duodenal cannula. Af ter 15 min, 5 g of D-xylose were injected in the duodenum, plasma leve ls 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 addi tion, the area under the curve: 3366 +/- 885 mg x min(-1) observed wit h this group was significantly greater than the other two groups: 1432 +/- 183 mg x min(-1) and 1337 +/- 280 mg x min(-1) respectively. No s tatistically significant differences in motor activity were observed b etween the different groups of peptides. Conclusions: A group of pepti des derived from casein was characterized by increasing D-those absorp tion. The presence of beta casomorphines might be the possible mechani sm involved.