Rodriguez de Turco E B, Spitzer J A
Department of Physiology, Louisiana State University Medical Center, New Orleans 70112.
Metabolism. 1988 Feb;37(2):164-70. doi: 10.1016/s0026-0495(98)90012-9.
The effect of chronic, nonlethal endotoxemia on the endogenous content and de novo biosynthesis of glycerolipids was investigated in rat hepatocytes. Continuous E. coli endotoxin (ET) infusion for 30 hours through a subcutaneously implanted mini-pump greatly altered the composition of membrane phospholipids. Sphingomyelin (SPH) and phosphatidylserine (PS) content increased by 56% and 29%, respectively, while the content of phosphatidylcholine (PC) decreased slightly (6%) as compared with saline-infused rats. These effects contrasted with those observed in pair-fed rats (whose food intake was matched to that voluntarily consumed by ET-infused animals). Food restriction induced a great depletion of phospholipid content, mainly phosphatidylethanolamine (PE), PC, phosphatidylinositol (PI), and PS, with no changes at the level of SPH as compared with control (fed ad libitum) rats. Triacylglycerol (TG) content was greatly decreased (66%) in ET-infused rats and the magnitude of the change and the fatty acid composition followed a pattern similar to that observed in pair-fed rats. The kinetics of [2-3H]-glycerol incorporation reflected efficient utilization of the precursor for de novo biosynthesis of glycerolipids. Labeling of the intermediate metabolite phosphatidic acid (PA) peaked at an earlier time (1 min) in ET-infused, and in pair-fed rats, as compared with saline-infused and control rats (3 min) respectively, and was followed by a later peak in diacylglycerol (DG) labeling. The metabolic flux thereafter in endotoxemia reflected a redirection toward the synthesis of TG and PI, while in pair-fed animals the label went mainly to PC, concomitantly with a great reduction in the uptake of label into PI.(ABSTRACT TRUNCATED AT 250 WORDS)
在大鼠肝细胞中研究了慢性非致死性内毒素血症对甘油脂质内源性含量和从头生物合成的影响。通过皮下植入的微型泵连续输注大肠杆菌内毒素（ET）30小时，极大地改变了膜磷脂的组成。与输注生理盐水的大鼠相比，鞘磷脂（SPH）和磷脂酰丝氨酸（PS）含量分别增加了56%和29%，而磷脂酰胆碱（PC）含量略有下降（6%）。这些效应与成对喂养大鼠（其食物摄入量与ET输注动物自愿消耗的量相匹配）中观察到的效应形成对比。食物限制导致磷脂含量大幅减少，主要是磷脂酰乙醇胺（PE）、PC、磷脂酰肌醇（PI）和PS，与对照（自由进食）大鼠相比，SPH水平没有变化。ET输注大鼠的三酰甘油（TG）含量大幅下降（66%），变化幅度和脂肪酸组成遵循与成对喂养大鼠中观察到的模式相似的模式。[2-3H]-甘油掺入的动力学反映了前体在甘油脂质从头生物合成中的有效利用。与分别输注生理盐水的大鼠和对照大鼠（3分钟）相比，ET输注大鼠和成对喂养大鼠中中间代谢产物磷脂酸（PA）的标记分别在较早时间（1分钟）达到峰值，随后二酰甘油（DG）标记出现较晚的峰值。内毒素血症后的代谢通量反映了向TG和PI合成的重新定向，而成对喂养动物中的标记主要进入PC，同时进入PI的标记摄取大幅减少。（摘要截断于250字）
