Siddiqui R A, Exton J H
Howard Hughes Medical Institute, Vanderbilt University School of Medicine, Nashville 37232.
Eur J Biochem. 1992 Dec 1;210(2):601-7. doi: 10.1111/j.1432-1033.1992.tb17460.x.
Hydrolysis of exogenous phosphatidylcholine (PtdCho) to 1,2-diacylglycerol by rat liver plasma membranes was stimulated by oleate concentrations as low as 0.1 mM. In the presence of 75 mM ethanol, the fatty acid also enhanced phosphatidylethanol (PtdEtOH) formation from PtdCho. These effects were also observed with linoleate and arachidonate, but not with saturated fatty acids or detergents, and were minimal in microsomes or mitochondria. Release of [3H]choline from exogenous Ptd[3H]Cho was stimulated by oleate, whereas phosphoryl[3H]choline formation was inhibited. Oleate and other unsaturated, but not saturated, fatty acids also stimulated the conversion of exogenous [14C]phosphatidic acid to [14C]diacylglycerol. These data are consistent with stimulatory effects of these fatty acids on both phospholipase D and phosphatidate phosphohydrolase in liver plasma membranes. The stimulatory effect of guanosine 5'-O-[3-thio]triphosphate) (20 microM) on PtdEtOH and diacylglycerol formation from PtdCho was enhanced by low concentrations of oleate. Phospholipase A2 also stimulated PtdEtOH and diacylglycerol formation from exogenous PtdCho. It is proposed that unsaturated fatty acids may play a physiological role in the regulation of diacylglycerol production through activation of phospholipase D and phosphatidate phosphohydrolase.
大鼠肝细胞膜可将外源性磷脂酰胆碱（PtdCho）水解为1,2 - 二酰甘油，低至0.1 mM的油酸浓度即可刺激该反应。在75 mM乙醇存在的情况下，脂肪酸还可增强由PtdCho生成磷脂酰乙醇（PtdEtOH）的过程。亚油酸和花生四烯酸也有这些作用，但饱和脂肪酸或去污剂则没有，且在微粒体或线粒体中作用极小。油酸可刺激外源性Ptd[3H]Cho释放[3H]胆碱，而抑制磷酸化[3H]胆碱的生成。油酸和其他不饱和脂肪酸（而非饱和脂肪酸）还可刺激外源性[14C]磷脂酸转化为[14C]二酰甘油。这些数据与这些脂肪酸对肝细胞膜中磷脂酶D和磷脂酸磷酸水解酶的刺激作用一致。低浓度油酸可增强鸟苷5'-O-[3 -硫代]三磷酸（20 microM）对由PtdCho生成PtdEtOH和二酰甘油的刺激作用。磷脂酶A2也可刺激由外源性PtdCho生成PtdEtOH和二酰甘油。有人提出，不饱和脂肪酸可能通过激活磷脂酶D和磷脂酸磷酸水解酶在二酰甘油生成的调节中发挥生理作用。
