The contribution of glucose and glutamine to energy metabolism in newborn pig enterocytes

Abstract

The aim of this work was to investigate glucose (2 mmol/L) and glutamine (2 mmol/L) metabolism in metabolically active enterocytes isolated from newborn pigs, as well as the contribution of these substrates to enterocyte energy metabolism. At birth or in 2-day-old suckling animals, the capacity of these cells to utilize glutamine was high (2.5 to 3.8 nmol/min. 10 6 cells), and the major products from glutamine were ammonia, glutamate, CO 2, and aspartate. Glucose decreased glutamine utilization by 25% but did not affect glutamine oxidation. The capacity of enterocytes to utilize glucose increased threefold between birth and 2 days of age (0.9 to 3.2 nmol/min. 10 6 cells). At birth, glutamine strongly reduced glucose utilization and oxidation, whereas in intestinal cells from 2-day-old suckling pigs only glucose oxidation was modified by glutamine. Oxygen consumption increased twofold in enterocytes isolated from suckling animals. Estimating potential ATP production from glutamine and glucose metabolism indicated that the complete oxidation of both substrates could contribute to 50% of total ATP turnover at both stages. In contrast, the contribution of aerobic glycolysis to ATP generation was low at birth and increased more than threefold in intestinal cells from 2-day-old suckling pigs.