Liver gluconeogenic metabolites in young and old rats during septic shock

Aged individuals have diminished resistance to severe sepsis and septic shock. Previous studies in young animals showed that the liver's gluconeogenic capacity was an important determinant of survival in shock states. This study compared hepatic carbohydrate intermediates from young rats and old rats to correlate changes during peritonitis septic shock with known differences in survival times. Old control rats had glucose 6-phosphate (G6P) concentrations two-fold higher than young controls, 354 +/- 49 nanomole/g wet liver vs 180 +/- 41, suggesting a reduced ability to convert hexose monophosphate precursor into blood sugar. There was a 53% increase in G6P levels in the peritonitis livers, to 540 +/- 155 nanomole/g liver while in young septic rats the G6P decreased 33 per cent. These opposite, highly significant changes in shock (P = 0.01) show the reduced ability of old animals to mobilize gluconeogenic precursors. Fructose 1,6-biphosphate (FBP) in old control liver was 14 +/- 3 nanomole/g liver and did not change in shock; in young rats, FBP was 7.0 +/- 3 nanomole and increased 230 per cent in shock, showing a different metabolic response in young and old animals. These data suggest older animals may be more vulnerable to shock because of lower gluconeogenic potential.