The pivotal role of the liver for glucose homeostasis resides within its ability to store large amounts of glucose in the form of glycogen, but also to rapidly release glucose into the circulation (1,2). Despite extensive studies on liver glycogen metabolism in vitro, studies in humans were limited to measurements of glycogen content by biopsy (3) before the introduction of in vivo 13C NMR spectroscopy for monitoring of hepatic glycogen in man (4).
