Glutamine and glucose metabolism in intraepithelial lymphocytes from pre- and post-weaning pigs

The metabolism of glutamine (Gln) and glucose was studied in intraepithelial lymphocytes (IEL) from 21-, 29- and 56-day-old pigs. Pigs were weaned at 21 days of age. Cells were incubated at 37°C in the presence of Krebs-Ringer bicarbonate buffer (pH 7.4) containing 1 mM [U¹⁴C]glutamine plus 5 mM glucose, or 5 mM [U¹⁴C]glucose plus 1 mM glutamine. Glucose was converted to lactate, pyruvate and CO₂, which accounted for 81, 11 and 8% of measured glucose carbon, respectively. Glutamine was metabolized mainly to glutamate (92% of Gln C) and ammonia, and to a lesser extent, to aspartate (4% of Gln C) and CO₂ (4% of Gln C). In the presence of both glucose and glutamine, glucose provided 2–3-fold more ATP to IELs than glutamine in 21–56-day-old pigs, on the basis of their measured end products. The rates of ammonia and glutamate production from glutamine in IELs from 29-day-old pigs were 112 and 90% greater than those in cells from 56-day-old pigs, respectively. The rates of glucose oxidation to CO₂ in IELs from 29-day-old pigs were elevated 56 and 64% respectively, compared with 21- and 56-day-old pigs. Elevated rates of substrate metabolism in IELs from 29-day-old post-weaning pigs indicated a metabolic alteration of these cells possibly due to changes in diet and intestinal bacterial population.