EFFECT OF DIETARY PEPTIDES ON PLASMA-LIPIDS AND ITS MECHANISM STUDIED IN RATS AND MICE

The present 4 experiments were planned to confirm our hypothesis that small quantity of intraluminal peptides enters into circulatory system and affects on lipid metabolism. In Experiments 1 and 2, rats and mice were fed diets of casein or two casein hydrolysate peptides for 2 and 3 weeks, respectively. Hypocholesterolemic effect in one of the peptides was observed in both animals. In Experiment 3, we administered small amount of the above peptides, amino acid mixture simulating casein pattern or saline to mice through tail vein daily for 10 days. Hypocholesterolemic effect was observed in the mice administered peptides but not in the mice administered saline and the amino acid mixture. In Experiment 4, entry of peptides into the circulatory system was shown with the everted sac of rat intestine. These results may indicate that small quantity of intraluminal peptides enter the circulatory system from lumen and affect on lipid metabolism.