Effect of intragastric triglyceride administration on glucose homeostasis in newborn pigs

The fasting hypoglycemia (1.78 +/- 0.29 mmol/l) which develops in 48-h-old pigs is partially reversed (3.85 +/- 0.55 mmol/l) after gastric administration of long-chain triglycerides (LCT). The increase in blood glucose induced by LCT feeding was not secondary to a decreased glucose utilization because glucose disappearance rate increased in LCT-fed piglets but resulted from a twofold increase in glucose appearance. By using the crossover-plot technique, the stimulation of hepatic gluconeogenesis induced by LCT feeding has been localized at 1) the level of pyruvate carboxylase owing to the twofold increase in hepatic acetyl-CoA concentration and 2) the level of glyceraldehyde-3-phosphate dehydrogenase secondary to the increase in reducing equivalents (NADH), which displaces this equilibrium reaction in the direction of gluconeogenesis. As blood lactate, pyruvate, and alanine concentrations increased after LCT feeding, the possible effects of LCT on pyruvate dehydrogenase in peripheral tissues are discussed. These data demonstrate that fatty acids stimulate hepatic gluconeogenesis in 48-h-old fasting piglets and underline the role of fat provision in the regulation of glucose homeostasis during the neonatal period in the pig.