Rössle C, Carpentier Y A, Richelle M, Dahlan W, D'Attellis N P, Elwyn D H, Stehle P, Fürst P
Clinical Nutrition Unit, University Hospital St. Pierre, Brüssel.
Infusionstherapie. 1991 Aug;18(4):167-71.
Medium-chain triglycerides are generally assumed to be metabolized independently of carnitine. The effects of infusing medium-chain triglycerides on plasma concentrations of carnitine derivatives and beta-hydroxybutyrate was studied in four healthy male adults. Glucose and amino acids were infused alone for three hours, then continued for another 5.5 hours together with a lipid emulsion containing only long-chain triglycerides or a mixture of medium-chain and long-chain triglycerides (50:50; w/w). During the fat-free infusion, the concentration of free carnitine rose, while the level of acylcarnitines decreased. Infusion of the mixed emulsion over 5.5 hours reduced free carnitine to lower values (32.4 +/- 4.7 mumols/L) than long-chain triglycerides infusion (44.4 +/- 2.7 mumols/L). By contrast, the plasma concentrations of short-chain acylcarnitines (12.1 +/- 3.3 vs. 5.4 +/- 1.9 mumols/L; p less than 0.01) and of beta-hydroxybutyrate (93 +/- 32 vs. 47 +/- 14 mumols/L; p less than 0.01) became significantly higher with the mixed emulsion than with long-chain triglycerides. These findings suggest that oxidation of medium-chain fatty acids is to some extent carnitine-dependent, whether or not transport into mitochondria is carnitine-mediated.
中链甘油三酯一般被认为是独立于肉碱进行代谢的。在四名健康成年男性中研究了输注中链甘油三酯对肉碱衍生物和β-羟基丁酸血浆浓度的影响。单独输注葡萄糖和氨基酸3小时，然后与仅含长链甘油三酯或中链和长链甘油三酯混合物（50:50；w/w）的脂质乳剂一起再持续输注5.5小时。在无脂肪输注期间，游离肉碱浓度升高，而酰基肉碱水平降低。5.5小时输注混合乳剂后，游离肉碱降至比输注长链甘油三酯更低的值（32.4±4.7μmol/L）（长链甘油三酯输注后为44.4±2.7μmol/L）。相比之下，混合乳剂组的短链酰基肉碱血浆浓度（12.1±3.3对5.4±1.9μmol/L；p<0.01）和β-羟基丁酸血浆浓度（93±32对47±14μmol/L；p<0.01）显著高于长链甘油三酯组。这些发现表明，无论脂肪酸进入线粒体的转运是否由肉碱介导，中链脂肪酸的氧化在一定程度上都依赖于肉碱。
