Effect of aging on hepatic carbohydrate metabolism in septic rats

Aged individuals have diminished resistance to severe sepsis and septic shock. Past work with animals suggested that an important determinant of survival was the ability of the liver to supply glucose. In this study, young adult (3 to 4 months) and old (24 months) Fischer 344 rats were fasted and subjected to cecal incisions producing a rapidly lethal peritonitis. We then determined gluconeogenic intermediates in the liver. In the old rats with peritonitis, hexosemonophosphates (HMP) increased 50% relative to control liver, whereas in the young animals with peritonitis, the substrate decreased 50%. The accumulation of HMP in the old rat liver cells indicates a failure to dephosphorylate glucose-6-phosphate (G6P). This increase in HMP is associated with a decline in hepatic glucose-6-phosphatase (G6Pase), the final enzyme in the gluconeogenic pathway, and is reflected in a significant reduction in serum glucose in old Fischer 344 rats when compared to young Fischer rats.