Hepatic adaptations to sucrose and fructose.

The liver is an important site of postprandial glucose disposal, accounting for the removal of up to 30% of an oral glucose load. The liver is also centrally involved in dietary lipid and amino acid uptake, and the presence of either or both of these nutrients can influence hepatic glucose uptake. The composition of ingested carbohydrate also influences hepatic glucose metabolism. For example, fructose can increase hepatic glucose uptake. In addition, fructose extraction by the liver is exceedingly high, approaching 50% to 70% of fructose delivery. The selective hepatic metabolism of fructose, and the ability of fructose to increase hepatic glucose uptake can, under appropriate conditions (eg, diets enriched in sucrose or fructose, high fructose concentrations), provoke major adaptations in hepatic metabolism. Potential adaptations that can arise in response to these conditions and putative mechanisms driving these adaptations are the subject of this review.