Froissart P, Unligil P, Aubry H, Proulx P
Department of Biochemistry, Faculty of Health Sciences, University of Ottawa, Canada.
Biochim Biophys Acta. 1989 Apr 26;1002(3):376-81. doi: 10.1016/0005-2760(89)90352-4.
Rat basophilic leukemia (RBL-2H3) cells were cultured in medium containing [3H]arachidonic acid and labelling of the different lipid fractions was followed with time. After up to 4 h of culture, the label was found mostly in phosphatidylcholine. After 8 h, labelling of phosphatidylethanolamine gradually exceeded that of phosphatidylcholine, until at 24 h, approximate equilibrium labelling of the lipid fractions was attained and 45% of the label was found in phosphatidylethanolamine, 35% in phosphatidylcholine, 18% in the phosphatidylserine/inositide fraction and the remainder in the neutral lipid fraction. Stimulation of cells with A23187 after 30 min of labelling caused release of [3H]arachidonic acid which was accountable by a decrease in radioactivity of phosphatidylcholine, whereas stimulation of cells after 24 h of labelling caused the release of radioactive arachidonic acid, which was accompanied by a decrease of label in both phosphatidylcholine and phosphatidylethanolamine. Incubation of the labelled cells with phorbol 12-myristate 13-acetate prior to ionophore addition enhanced both the release of [3H]arachidonic acid and its metabolites and the decrease in label of the same phospholipids as those affected by ionophore alone. Under our conditions, the enhancement effects of phorbol ester were greatest after 2-5 min of preincubation, prior to ionophore addition. The results suggest that in basophilic leukemia cells, arachidonic acid release proceeds from several pools of phospholipids and that the activity of the phospholipase(s) involved is modulated by protein kinase C.
将大鼠嗜碱性白血病（RBL - 2H3）细胞培养于含有[3H]花生四烯酸的培养基中，并随时间追踪不同脂质组分的标记情况。培养长达4小时后，标记物主要存在于磷脂酰胆碱中。8小时后，磷脂酰乙醇胺的标记逐渐超过磷脂酰胆碱，直至24小时，脂质组分达到近似平衡标记，45%的标记物存在于磷脂酰乙醇胺中，35%存在于磷脂酰胆碱中，18%存在于磷脂酰丝氨酸/肌醇磷脂组分中，其余存在于中性脂质组分中。标记30分钟后用A23187刺激细胞导致[3H]花生四烯酸释放，这可通过磷脂酰胆碱放射性的降低来解释，而标记24小时后刺激细胞导致放射性花生四烯酸释放，同时伴随着磷脂酰胆碱和磷脂酰乙醇胺中标记物的减少。在添加离子载体之前，用佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯孵育标记细胞，增强了[3H]花生四烯酸及其代谢产物的释放以及与单独受离子载体影响的相同磷脂中标记物的减少。在我们的条件下，在添加离子载体之前预孵育2 - 5分钟后，佛波醇酯的增强作用最大。结果表明，在嗜碱性白血病细胞中，花生四烯酸的释放来自几个磷脂池，并且所涉及的磷脂酶的活性受蛋白激酶C调节。
