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1乙醇在体内的代谢途径乙醇进入体内后通过胃肠道吸收,仅有2%～10%由呼吸道,尿液和汗腺以原形排出,其余90%在肝脏内氧化,很少在肝外代谢。经肝脏代谢的乙醇约80%通过乙醇脱氢酶转化为乙醛,约20%通过微粒体乙醇氧化酶转化为乙醛,乙醛再经过乙醛脱氢酶(ALDH)转化为乙酸,后者以乙酰辅酶A的形式进入三羧酸循环,氧化成二氧化碳和水。口服乙醇90%～98%是通过以下三个途径代谢:①饮酒后,首先启动0级经典途径。即通过胞质内的乙醇脱氢酶(ADH);②过氧化小体内的触酶过氧化氢酶(CAT)进行代谢;③当血乙醇浓度过高时,也启动一级代谢途径,即通过内质网中的微粒体乙醇氧化代谢系统(MEOS)进行代谢,通过这三种酶的作用将乙醇氧化分解为乙醛。乙醛对肝脏有直接毒性作用。可以造成肝细胞变性坏死而引发一系列变化。此外,MEOS代谢过程需要氧及细胞色素P450参与,其中可被乙醇诱导的部分称为P4502E1。过量酒精的摄入对器官的损伤不仅仅是酒精本身,还有酒精代谢的效应
1 Ethanol in vivo metabolic pathway After ethanol into the body through the gastrointestinal tract absorption, only 2% to 10% of the respiratory tract, urine and sweat glands to the original form of excretion, and the remaining 90% in the liver oxidation, rarely in extrahepatic metabolism. Approximately 80% of the ethanol metabolized by the liver is converted to acetaldehyde by alcohol dehydrogenase, about 20% is converted to acetaldehyde by microsomal ethanol oxidase, and acetaldehyde is converted to acetic acid by acetaldehyde dehydrogenase (ALDH) Into the tricarboxylic acid cycle in the form of acetyl-CoA, oxidation to carbon dioxide and water. Oral ethanol 90% to 98% is metabolized by the following three ways: ① after drinking, first start 0 class pathways. Namely through the cytoplasmic alcohol dehydrogenase (ADH); ② peroxisomal catalase (CAT) metabolism; ③ when the blood alcohol concentration is too high, but also to start a metabolic pathway, that is, by Endoplasmic reticulum in the body’s metabolism of ethanol oxidation system (MEOS) metabolism, the role of these three enzymes will be oxidized ethanol into acetaldehyde. Acetaldehyde has a direct toxic effect on the liver. Can cause degeneration and necrosis of liver cells and trigger a series of changes. In addition, MEOS metabolism requires oxygen and cytochrome P450 involvement, which can be induced by ethanol called P4502E1. Excessive alcohol intake on the organ damage is not only alcohol itself, as well as the effect of alcohol metabolism