Absorption of amino acids from the human mouth.

Certain amino acids were transported across buccal mucosa in vivo by a carrier-mediated process. Metabolic loss of L-amino acids from the mouth in a 5 min test period was negligible. The buccal mucosal transport process was stereospecific for most L-amino acids tested.

Characteristics of L-citrulline transport across rat small intestine in vitro.

The amino acid L-citrulline is an important intermediate of urea cycle and a key precursor for arginine biosynthesis. We have examined the characteristics of citrulline transport across the everted sacs of the rat small intestine. Our studies suggest that the optimal site of citrulline absorption is middle to lower ileum.