Absorption of intact peptides: studies on transport of protein digests and dipeptides across rat small intestine in vitro.

Passage of intact peptides across isolated rat small intestine has been studied during luminal perfusion with partial digests of proteins or with dipeptides. Significant passage of intact peptide does occur, the amount depending upon the luminal concentration. It probably reflects the 'digestibility' of the protein or protein digest. Previous studies are discussed and, although intact peptide transport is probably not of major nutritional importance, it is suggested that the pathophysiological significance of this process and of peptidaemia merits further attention.