Fig. 1.

L-Arg once in the cell can be metabolized by Arginase. The products of this enzyme are: L-Ornithine, which is further cleaved to polyamines by ornithine decarboxylase (ODC), L-proline by ornithine aminotransferase (OAT), and urea. These compounds exert negative effects on glucose metabolism. When L-Arg is cleaved in nitric oxide (NO) and L-citrulline by the nitric oxide synthase (NOS), these compounds have positive effects on glucose metabolism, also exerting beneficial action on the cardiovascular system