Figure 1

Overview of the major aspects of hepatic metabolism of glucose and fructose. Key points emphasized in the text: the two sugars converge at the level of the triose-phosphates (dihydroxyacetone-phosphate (DHAP) and glyceraldehyde-3-P (Ga-3-P)). Conversion of fructose to the triose-phosphates is unidirectional but fructose-1-phosphate is a positive effector of glucokinase and regulates glycogen synthesis by activating the synthase and inhibiting phosphorylase. The last effect may be different between species. Light blue arrows show the path of gluconeogenesis from fructose leading to glucose-6-P which, in turn, can produce glucose or be incorporated into glycogen.