Wollin A, Wang X, Tso P
Department of Physiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E5.
Am J Physiol. 1998 Oct;275(4):R969-75. doi: 10.1152/ajpregu.1998.275.4.R969.
Diamine oxidase is continuously released from the intestinal mucosa and carried to the circulation by the lymphatics. The effect of nutrients on this release was examined. Rats were prepared with duodenal and intestinal lymph cannulas. Test mixtures of lipid emulsions containing triolein, oleic acid, or tricaprylin and solutions of carbohydrate and protein were infused into the duodenum. The enzyme release and triglyceride transport were determined and in some experiments were done in the presence and absence of Pluronic L-81, an inhibitor of chylomicron formation, and aminoguanidine, an inhibitor of diamine oxidase activity. The data indicate that nonlipid nutrients did not increase diamine oxidase activity in the intestinal lymph, but the mucosal tissue content was significantly reduced in the distal small intestine, particularly after protein infusion. Triglycerides and fatty acids increased diamine oxidase in the intestinal lymph, and the longer-chain triglyceride was more effective. Inhibition of triglyceride transport did not interfere with the enzyme release, and the inhibition of diamine oxidase activity had no significant effect on lipid absorption. According to our observations, only lipids increase intestinal lymph diamine oxidase. Nonfat nutrients appear to increase diamine oxidase in the intestinal lumen. Diamine oxidase is not directly required for lipid absorption.
二胺氧化酶持续从肠黏膜释放，并通过淋巴管进入循环系统。研究了营养物质对这种释放的影响。给大鼠制备十二指肠和肠淋巴管插管。将含有三油酸甘油酯、油酸或三辛酸甘油酯的脂质乳剂与碳水化合物和蛋白质溶液的测试混合物注入十二指肠。测定酶释放和甘油三酯转运，在一些实验中，在有和没有普流罗尼克L-81（一种乳糜微粒形成抑制剂）和氨基胍（一种二胺氧化酶活性抑制剂）的情况下进行。数据表明，非脂质营养物质不会增加肠淋巴中的二胺氧化酶活性，但在远端小肠中黏膜组织含量显著降低，尤其是在输注蛋白质后。甘油三酯和脂肪酸会增加肠淋巴中的二胺氧化酶，且长链甘油三酯更有效。抑制甘油三酯转运不会干扰酶释放，抑制二胺氧化酶活性对脂质吸收没有显著影响。根据我们的观察，只有脂质会增加肠淋巴中的二胺氧化酶。非脂肪营养物质似乎会增加肠腔内的二胺氧化酶。脂质吸收并不直接需要二胺氧化酶。
