EFFECT OF PARENTERAL ADMINISTRATION OF SHORT-CHAIN TRIGLYCERIDES ON LEUCINE METABOLISM

The present studies investigated the effects of intravenous administra tion of the short-chain triglyceride triacetin on leucine metabolism i n dogs. Animals received infusions of triacetin at 1.0 x estimated res ting energy expenditure (REE), hyperenergetic triacetin at 1.5 x REE, glycerol, or saline during infusion of [1-C-14]leucine. During both tr iacetin infusions, plasma alpha-ketoisocaproate concentrations increas ed (P < 0.05). During triacetin infusion at 1.5 REE, the plasma leucin e concentration decreased (P < 0.05) and leucine rate of appearance de creased by almost-equal-to 19% (P < 0.05); this was significantly grea ter than the changes that occurred during triacetin at 1.0 x REE and g lycerol (P < 0.05). There was no difference in leucine oxidation betwe en the dogs given triacetin at 1.0 x REE and control groups, whereas l eucine oxidation decreased by 53% during triacetin infusion at 1.5 x R EE (P < 0.05). Nonoxidative leucine disappearance, an indicator of pro tein synthesis, did not change in any of the studies. These results in dicate that triacetin has effects on leucine metabolism similar to tho se previously reported with long-chain triglyceride emulsions. Because of its water solubility, lack of toxicity, and favorable effects on p rotein metabolism, further studies are warranted regarding the use of triacetin as a parenteral nutrient.