Morotomi M, LoGerfo P, Weinstein I B
Department of Surgery, Columbia-Presbyterian Medical Center Columbia University, New York, NY 10032.
Biochem Biophys Res Commun. 1991 Dec 31;181(3):1028-34. doi: 10.1016/0006-291x(91)92040-q.
In a previous paper we demonstrated that human fecal bacteria can convert phosphatidylcholine to diacylglycerol (DAG), an activator of protein kinase C. The present study demonstrates that several foods contain appreciable levels of DAG, especially certain vegetable oils. On the other hand, when rats were administered [14C]-labeled DAG by intragastric intubation less than 0.1% of the administered radioactivity was recovered as DAG in the feces. Thus only negligible amounts of dietary DAG actually reach the colon. When [14C]DAG was injected directly into ligated segments of rat colon we found appreciable uptake of the intact DAG by the mucosal cells. The major metabolite was arachidonic acid, suggesting that the DAG lipase pathway is more active than the DAG kinase pathway in these cells. Taken together, these results are consistent with our hypothesis that much of the DAG present in the colonic lumen is produced by the intestinal bacteria and that this DAG can actually enter the colonic mucosal cells, where it might influence their function.
在之前的一篇论文中，我们证明了人类粪便细菌可将磷脂酰胆碱转化为蛋白激酶C的激活剂二酰基甘油（DAG）。本研究表明，几种食物含有相当水平的DAG，尤其是某些植物油。另一方面，当通过胃内插管给大鼠施用[14C]标记的DAG时，粪便中回收的施用放射性不到0.1%以DAG形式存在。因此，实际上只有可忽略不计的膳食DAG到达结肠。当将[14C]DAG直接注射到大鼠结肠的结扎段时，我们发现黏膜细胞对完整的DAG有明显摄取。主要代谢产物是花生四烯酸，这表明在这些细胞中DAG脂肪酶途径比DAG激酶途径更活跃。综上所述，这些结果与我们的假设一致，即结肠腔内存在的大部分DAG是由肠道细菌产生的，并且这种DAG实际上可以进入结肠黏膜细胞，在那里它可能会影响细胞功能。
