A Comparison of the Transport Systems for Amino Acids in Brain, Intestine, Kidney and Tumour

Abstract

Publisher Summary Amino acids enter many tissues by a process of active transport and can often be taken up into the cell against a concentration gradient, thus implying the existence of carrier mechanism. There are different carrier mechanisms for different groups of amino acid and this paper is an attempt to indicate how those groups probably differs from one tissue to another. It is divided into two parts, firstly a brief review of the different transport systems that appear to exist in certain tissues (brain, small intestine, kidney and tumor), and secondly some of the relevant experimental work which has been carried out in those tissues. The paper describes competition that can occur between amino acids for a common transport mechanism. If one amino acid shares the same transport system as a second amino acid, it will displace the second amino acid from the carrier. This is seen experimentally as an inhibition of the uptake of the second amino acid in the presence of the first.