Rabinowitz J L, Cardwell T, Bassett D J
Am J Physiol. 1981 Apr;240(4):E435-40. doi: 10.1152/ajpendo.1981.240.4.E435.
The utilization of glucose, palmitate, and oleate for the synthesis of lung lipids was studied in isolated rat lungs. Lungs were ventilated with 5% CO2 in air and perfused for 100 min with a Krebs-Ringer bicarbonate buffer (pH 7.4), containing 3% fatty acid-free albumin and either 5.6 mM [U-14C]glucose or 0.25 mM [1-14C]palmitate, or 0.25 mM [1-14C]-oleate. At the end of 100 min of perfusion with these precursors, between 73 and 85% of total lipid 14C was recovered as phospholipid. Glucose carbon was mainly incorporated into triglyceride fatty acids (TG-FA) and phosphatidylcholine fatty acids (PC-FA) of 16- and 18-carbon chain length. After perfusion with [14C]palmitate and [14C]oleate, only 65 and 20% of 14C was recovered as PC 16-carbon and 18-carbon FA, respectively. The remaining 14C was mainly recovered as FA shorter than the 14C precursors. Schmidt degradation analysis of lipid FA demonstrated considerable labeling of alkyl carbons on perfusion with the carboxyl-labeled precursors, indicating that FA degradation products were used for synthesis of lipid FA. This process was enhanced on addition of glucose to the perfusate.
在离体大鼠肺中研究了葡萄糖、棕榈酸酯和油酸酯用于肺脂质合成的情况。肺用含5%二氧化碳的空气进行通气，并在含有3%无脂肪酸白蛋白以及5.6 mM [U-¹⁴C]葡萄糖或0.25 mM [¹-¹⁴C]棕榈酸酯或0.25 mM [¹-¹⁴C]油酸酯的 Krebs-Ringer 碳酸氢盐缓冲液（pH 7.4）中灌注100分钟。在用这些前体灌注100分钟结束时，总脂质¹⁴C的73%至85%以磷脂形式回收。葡萄糖碳主要掺入16碳和18碳链长度的甘油三酯脂肪酸（TG-FA）和磷脂酰胆碱脂肪酸（PC-FA）中。在用[¹⁴C]棕榈酸酯和[¹⁴C]油酸酯灌注后，分别只有65%和20%的¹⁴C以16碳和18碳的PC脂肪酸形式回收。其余的¹⁴C主要以比¹⁴C前体短的脂肪酸形式回收。脂质脂肪酸的施密特降解分析表明，在用羧基标记的前体灌注时，烷基碳有相当程度的标记，这表明脂肪酸降解产物被用于脂质脂肪酸的合成。向灌注液中添加葡萄糖可增强这一过程。
