Rates of absorption by rat intestine of pancreatic hydrolysates of proteins and their corresponding amino acid mixtures.

1. Though the occurrence of intestinal mucosal uptake of intact peptides, with cellular hydrolysis to amino acids, has been established, the importance of this mode of absorption in protein absorption is not known. This paper describes a comparison of the rates of intestinal absorption of pancreatic hydrolysates of four proteins with . those of the corresponding acid hydrolysates or amino acid mixtures. 2. The results show that the absorption of pancreatic hydrolysates, consisting largely of small peptides of two to six amino acid residues, is substantially more rapid than that of the corresponding mixtures of free amino acids. This shows that the small intestine has a high capacity for absorption from mixtures of small peptides such as might be produced during protein digestion, and supports the hypothesis that mucosal uptake of intact oligopeptides is an important mode of protein absorption.