Kayden H J, Senior J R, Mattson F H
J Clin Invest. 1967 Nov;46(11):1695-703. doi: 10.1172/JCI105660.
The absorption of fat was studied in five male subjects with cannulation of the thoracic duct in the neck by the administration of doubly labeled monoglycerides, or triglyceride as well as labeled free glycerol or labeled free oleic acid, by gastric or duodenal intubation.Total recoveries of the administered glyceride radioactivity from the lymph lipids ranged from 35 to 53% for the glycerol label (tritium) and from 35 to 57% for the fatty acid label ((14)C). The recovery of administered radioactive free glycerol in lymph lipids was only 4.1%, even when given in mixture with bile salts, fatty acid, and monoglyceride.A comparison of the isotope ratios of the two components (glycerol and fatty acid) of the lymph glycerides with the ratios of these components of the original meal glyceride showed little change during the initial period of fat absorption, indicating that the doubly labeled monoglycerides passed into the lymph intact. During the later part of the period of major fat absorption, the ratios in lymph lipids changed due to loss of glycerol representation, indicating monoglyceride hydrolysis and portal venous diversion of free glycerol. Confirmation of the intact nature of 2-monoglyceride during absorption was made by analyzing the amount and position of the labeled fatty acid in the lymph triglycerides. The percentage of labeled fatty acid in the various positions of the lymph triglycerides was virtually identical with that of the meal during the initial period of fat absorption and then changed reflecting isomerization of fatty acids and subsequent complete hydrolysis of the glycerides.The 2-monoglyceride pathway appears to be the major route of fat absorption for man during normal digestion and absorption of dietary triglyceride.
通过胃管或十二指肠管饲法给予双标记甘油单酯、甘油三酯以及标记的游离甘油或标记的游离油酸，对5名颈部胸导管插管的男性受试者的脂肪吸收情况进行了研究。从淋巴脂质中回收的甘油酯放射性总量，甘油标记（氚）为35%至53%，脂肪酸标记（¹⁴C）为35%至57%。即使与胆汁盐、脂肪酸和甘油单酯混合给予，淋巴脂质中给予的放射性游离甘油的回收率也仅为4.1%。将淋巴甘油酯的两种成分（甘油和脂肪酸）的同位素比率与原始膳食甘油酯的这些成分的比率进行比较，发现在脂肪吸收的初始阶段变化不大，这表明双标记甘油单酯完整地进入了淋巴。在主要脂肪吸收期的后期，淋巴脂质中的比率因甘油代表性的丧失而发生变化，这表明甘油单酯水解以及游离甘油的门静脉分流。通过分析淋巴甘油三酯中标记脂肪酸的量和位置，证实了吸收过程中2-甘油单酯的完整性质。在脂肪吸收的初始阶段，淋巴甘油三酯各个位置的标记脂肪酸百分比与膳食中的几乎相同，随后发生变化，反映了脂肪酸的异构化以及甘油酯的后续完全水解。在正常消化和吸收膳食甘油三酯过程中，2-甘油单酯途径似乎是人体脂肪吸收的主要途径。
