Fat absorption during inhibition of protein synthesis: studies of lymph chylomicrons.
Fat absorption during inhibition of protein synthesis: studies of lymph chylomicrons.
复制标题
抑制蛋白质合成期间的脂肪吸收：淋巴乳糜微粒的研究。
DOI：
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发表时间：
1972
影响因子：
15.9
通讯作者：
K. Isselbacher
中科院分区：
文献类型：
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作者：
R. Glickman;K. Kirsch;K. Isselbacher
以肠系膜淋巴瘘大鼠为模型，研究了蛋白质合成抑制对胶束溶液中油酸吸收的影响。用示踪剂量油酸-(14)C标记的油酸胶束溶液经十二指肠给药给留置肠系膜淋巴管的大鼠。脂肪注射前1h，腹腔注射乙酰氧基环己亚胺(ACH)0.25 mg/kg，抑制蛋白质合成。用油酸-(14)C标记的淋巴乳糜粒，从对照组和蛋白抑制动物体内注入脂肪后不同时间收集，用蔗糖密度梯度离心法测定其大小的变化。在对照组动物中，在甘油三酯最大吸收期间，乳糜粒的大小有一过性的增加；然而，在蛋白质抑制的动物中，乳糜粒的大小直到脂肪注射后4小时才显著而持续地增加。两组洗涤乳糜粒的甘油三酯和磷脂测定表明，在蛋白质合成被抑制后，甘油三酯/磷脂比率更大，支持更大的乳糜粒尺寸。两组淋巴的电子显微镜进一步证实，在蛋白质合成被抑制后，乳糜粒明显增大。有人认为，在蛋白质合成受到抑制的情况下，尺寸的增加保留了乳胶粒表面的成分，即载脂蛋白。这些研究清楚地表明，肠道对蛋白质合成的抑制与肠淋巴乳糜粒大小的增加有关，并支持蛋白质合成在乳糜粒的形成和从粘膜细胞到淋巴的运输中起重要作用的概念。
The effect of protein synthesis inhibition on the absorption of oleic acid from micellar solution was studied in mesenteric lymph fistula rats. A micellar solution of oleic acid labeled with tracer doses of oleic acid-(14)C was administered by intraduodenal infusion to rats with indwelling mesenteric lymph cannulas. Protein synthesis was inhibited by intraperitoneal acetoxycycloheximide (ACH), 0.25 mg/kg, 1 hr before lipid infusion. Lymph chylomicrons labeled with oleic acid-(14)C were collected from control and protein inhibited animals at various times after lipid infusion and subjected to sucrose density gradient centrifugation to determine changes in size. In control animals there was a transient increase in chylomicron size during maximal triglyceride absorption; however, in protein-inhibited animals there was a marked and sustained increase in chylomicron size as late as 4 hr after lipid infusion. Triglyceride and phospholipid determinations on washed chylomicrons from both groups indicated a greater triglyceride/phospholipid ratio after protein synthesis inhibition supporting a greater chylomicron size. Electron microscopy of lymph from both groups further confirmed a markedly increased chylomicron size after protein synthesis inhibition. It is proposed that an increase in size conserves chylomicron surface components, i.e. apoprotein, during conditions of inhibition of protein synthesis. These studies clearly demonstrate that the intestinal inhibition of protein synthesis is associated with an increase in the size of intestinal lymph chylomicrons and support the concept that protein synthesis is important in the formation and transport of chylomicrons from the mucosal cell into the lymph.