抄録
In order to study the variability of intestinal transport systems for amino acid and peptide, the effects of quantity and quality of dietary protein on the absorption of L-leucine and glycylglycine were investigated in situ in the rat jejunum. The absorption activities for both amino acid and dipeptide changed in a similar manner in response to the dietary levels of casein ; decreasing below 10%, remaining nearly constant between 10 and 50%, and increasing above a 50% casein level. Similar results were obtained with wheat gluten. At an equal dietary protein level (equivalent to 10% casein), the absorption activities for L-leucine and glycylglycine in rats fed with a zein or gelatin diet were lower than those in animals fed with a casein or gluten diet. A high correlation was observed between the absorption activity for L-leucine and that for glycylglycine in all dietary groups. The results clearly indicate that jejunal absorption activity for glycylglycine could be altered in parallel with that for L-leucine by changes of the quantity and quality of dietary protein.
