Ockner R K, Hughes F B, Isselbacher K J
J Clin Invest. 1969 Nov;48(11):2079-88. doi: 10.1172/JCI106174.
The transport of endogenous lipids in the lipoproteins of mesenteric lymph was studied in fasting rats with mesenteric lymph fistulas. The lymph was found to contain, in addition to chylomicrons (S(f) >400), a significant amount of another, more dense, triglyceride-rich fraction, the very low density lipoproteins (VLDL), which showed a peak S(f) of 102. The VLDL differed from chylomicrons not only in flotation, but also in per cent lipid composition and electrophoretic mobility in agarose gel. The VLDL fraction was found to contain 47% of the triglyceride and 54% of the cholesterol of fasting lymph and, in the fasting state, was the major lipoprotein species present. When cholestyramine resin was administered intraduodenally, or bile flow was acutely diverted from the intestine, it was demonstrated that the lipids in lymph VLDL, like those in chylomicrons, were derived from the intestine and bile. These data indicate that the VLDL in intestinal lymph are not derived from the plasma but are of intestinal origin. Because certain properties of lymph VLDL were similar to those reported for plasma VLDL (per cent lipid composition, flotation coefficient, and continuing entry into plasma in the fasting state), additional comparisons between these fractions were made. Although lymph VLDL moved to the alpha(2) region in agarose gel, when they were mixed with VLDL-free serum immediately before electrophoresis they showed the alpha(2) mobility of rat serum VLDL. Furthermore, immunoelectrophoretic comparison of partially delipidated lymph and serum VLDL revealed that these fractions shared in common their major apoprotein, and possibly others as well. The fatty acid composition of lymph and serum triglycerides, as determined by gas-liquid chromatography, revealed that although they were generally similar, differences existed which most likely reflected the presence in serum of triglycerides of hepatic origin. These experiments demonstrate the importance of intestinal VLDL in the transport of endogenous lipids in mesenteric lymph in the fasting state. The similarities between intestinal lymph VLDL and plasma VLDL suggest that the latter may be derived in part from the former.
在患有肠系膜淋巴瘘的禁食大鼠中，研究了肠系膜淋巴中脂蛋白内源性脂质的转运情况。发现淋巴中除了含有乳糜微粒（S(f) >400）外，还含有大量另一种密度更高、富含甘油三酯的组分，即极低密度脂蛋白（VLDL），其S(f)峰值为102。VLDL与乳糜微粒的不同之处不仅在于漂浮特性，还在于脂质组成百分比以及在琼脂糖凝胶中的电泳迁移率。发现VLDL组分含有禁食淋巴中47%的甘油三酯和54%的胆固醇，并且在禁食状态下是主要的脂蛋白种类。当十二指肠内给予消胆胺树脂，或急性改变胆汁从肠道的引流时，证明淋巴VLDL中的脂质与乳糜微粒中的脂质一样，都来源于肠道和胆汁。这些数据表明，肠道淋巴中的VLDL并非来源于血浆，而是起源于肠道。由于淋巴VLDL的某些特性与报道的血浆VLDL相似（脂质组成百分比、漂浮系数以及在禁食状态下持续进入血浆），因此对这些组分进行了进一步比较。尽管淋巴VLDL在琼脂糖凝胶中迁移至α(2)区域，但在电泳前立即与无VLDL血清混合时，它们显示出大鼠血清VLDL的α(2)迁移率。此外，对部分脱脂的淋巴和血清VLDL进行免疫电泳比较发现，这些组分共有其主要载脂蛋白，可能还有其他载脂蛋白。通过气液色谱法测定的淋巴和血清甘油三酯的脂肪酸组成表明，尽管它们总体上相似，但存在差异，这很可能反映了血清中存在肝脏来源的甘油三酯。这些实验证明了肠道VLDL在禁食状态下肠系膜淋巴内源性脂质转运中的重要性。肠道淋巴VLDL与血浆VLDL之间的相似性表明，后者可能部分来源于前者。
