2012 年 1 巻 1 号 p. 145-150
Minor amounts of glucose incorporated into the cells is metabolized via the hexosamine biosynthetic pathway, resulting in the production of uridine-5’-diphosphate-N-acetylglucosamine (UDP-GlcNAc), which is utilized as a donor substrate for the N- and O-linked glycosylation of extracellular and membrane proteins in the Golgi apparatus, or for the O-linked GlcNAc modification (O-GlcNAcylation) of intracellular proteins in the cytosol. In particular, O-GlcNAcylation, the addition of GlcNAc to serine/threonine residues, is reversibly regulated by the enzymatic activities of O-GlcNAc transferase (OGT) and O-GlcNAcase. Since OGT activity is sensitive to the intracellular UDP-GlcNAc level, flux via the hexosamine pathway influences O-GlcNAcylation. Actually, excess flux via the hexosamine pathway and resultant increased O-GlcNAcylation are associated with several pathophysiological conditions, including insulin resistance. To date, there are several studies addressing the effects of exercise on the hexosamine pathway and O-GlcNAcylation. Thus, this short review focuses on the relationships among exercise, the hexosamine pathway, O-GlcNAcylation, and insulin resistance.