An alternative mechanism for guanidinoacetic acid to affect methylation cycle

Abstract

Guanidinoacetic acid (also known as glycocyamine; GAA) is an endogenous substance which occurs in humans and plays a central role in the biosynthesis of creatine. The formation of creatine from GAA consumes methyl groups, and increases production of homocysteine. GAA may have the potential to stimulate insulin secretion. Insulin reduces plasma homocysteine and raises methyl group supply. It is possible that the ability of GAA to trigger the insulin secretion modulates methyl group metabolism, and comparatively counterbalance for the direct effect of GAA on increased methylation demand. Possible insulinotropic effect of GAA may contribute to total in vivo methylation demand during biotransformation.