Glutamine promotes triglyceride absorption in a dose-dependent manner

Abstract

Dietary proteins may play a role in lipid absorption. Whether amino acids are specifically involved is unknown. We hypothesized that enterally administered l-glutamine (l-Gln) given with a lipid meal increases triglyceride (TG) absorption in rats. Mesenteric lymph fistulae and gastroduodenal feeding tubes were placed in adult male Sprague-Dawley rats. The animals received an enteral bolus of Intralipid (5 ml) followed by enteral infusion of increasing concentrations of l-Gln in saline (0, 85, 170, or 340 mM) or equimolar concentrations of the inactive isomer d-Gln or an essential amino acid mixture without Gln. Lymph was collected continuously for 6 h and analyzed for TG content. Animals infused with 85 mM l-Gln had a 64% increase in total TG output vs. controls ( P < 0.05) despite no difference in lymph flow rate. Total TG output for animals infused with 340 mMl-Gln declined by 43% vs. controls ( P < 0.05). The effect of Gln in promoting lymphatic fat transport is specific to l-Gln and not shared by d-Gln or an equivalent amino acid mixture. l-Gln is capable of either promoting or impairing lymphatic TG transport in a dose-dependent manner.