Determination of the Route of Medium-Chain and Long-Chain Fatty Acid Absorption by Direct Measurement in the Rat

ABSTRACT. Background: Medium-chain triglycerides are used for the treatment of malabsorptive states. We measured directly the absorption of medium- and long-chain fatty acids via the mesenteric lymphatics and portal vein in normal animals. These results may be useful in guiding therapy for short-bowel syndrome. Methods: Under anesthesia, male Lewis rats (n = 6) underwent placement of jugular and portal venous lines, mesen-teric lymphatic duct cannula, and a duodenal tube. After recov-ery, a 0.3 % lauric acid (C12:0) and 0.37 % palmitic acid (C16:0) solution solublized with 3.25 mmol/L lecithin and 23.75 mmol/L taurocholic acid in phosphate-buffered saline was infused at a rate of 3 mL/h via the duodenal tube. After stabilization of lym-phatic flow (6 hours), a pulse of radiolabeled lauric and palmitic acid was given via the duodenal tube; absorption was measured by collection of lymphatic fluid and sampling of the portal an