Amino acids have an influence on the function of organs, glands, tendons and arteries. Some of them play crucial roles in the control of gene expression by controlling the initiation phase of mRNA translation. Furthermore, recent studies have revealed that some kinds of amino acids directly participate in important signal transduction in the immune system. Glutamine, leucine and arginine play crucial roles in intestinal growth, integrity, and function through cellular signaling mechanisms. In this paper, we review amino acid signal transduction in the intestinal function