Effect of Endogenous Insulin on Human Amino Acid Metabolism

This study describes the effect of endogenous insulin on free plasma amino acids. The secretion of insulin was provoked by means of a standard glucose tolerance test.

Four healthy males responded by a drop in the levels of all twenty-two plasma amino acids, which were measured. In four insulin-dependent diabetics the glucose tolerance experiment effected only slight decreases in nineteen of twenty-two amino acids. Ornithine and histidine decreased significantly, whereas phenylalanine increased.

The over-all result indicates that endogenous insulin reduces the levels of the majority, if not all, free plasma amino acids.