1981 Volume 89 Issue 2 Pages 407-410
The effect of amino acids on insulin responsiveness in epididymal adipose tissue was examined. It was found that insulin-stimulated glucose oxidation in fat cells was significantly inhibited by glycine, alanine, valine, leucine, isoleucine, cysteine, methionine, lysine, phenylalanine, and proline. The effect of insulin on glucose incorporation into triglyceride is also severely diminished by these amino acids. In addition, alanine reduced the incorporation of precursors ([U-14C]glucose or [1-14C]palmitate) into triglyceride both in vitro and in vivo. The K1 values of alanine were 0.4 and 0.5mM toward the precursors of glucose and palmitate, respectively. The mechanism of reduction of insulin responsiveness in rat adipose tissue is discussed on the basis of these results.