Four grams of glucose

Department of Molecular Physiology and Biophysics and Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, Tennessee Submitted 7 July 2008 ; accepted in final form 1 October 2008 ABSTRACT Four grams of glucose circulates in the blood of a person weighing 70 kg. This glucose is critical for normal function in many cell types. In accordance with the importance of these 4 g of glucose, a sophisticated control system is in place to maintain blood glucose constant. Our focus has been on the mechanisms by which the flux of glucose from liver to blood and from blood to skeletal muscle is regulated. The body has a remarkable capacity to satisfy the nutritional need for glucose, while still maintaining blood glucose homeostasis. The essential role of glucagon and insulin and the importance of distributed control of glucose fluxes are highlighted in this review. With regard to the latter, studies are presented that show how regulation of muscle glucose uptake is regulated by glucose delivery to muscle, glucose transport into muscle, and glucose phosphorylation within muscle. insulin; mice; rat; dog; glycogen; epinephrine; hexokinase; glucose transport; glucose delivery Address for reprint requests and other correspondence: D. H. Wasserman, Light Hall Rm. 702, Vanderbilt Univ. School of Medicine, Nashville, TN 37232 (e-mail: david.wasserman{at}vanderbilt.edu )