多种化学性质和生物活性不同的化合物均可使肝脏产生病变。大部分外源性化合物不论其毒性如何均需在体内、特别在肝内代谢(或生物转化)并变为其代谢物质,代谢物质的毒性可高于或低于原化合物,部分还可导致畸形,致突变和致癌等。但亦有一些化合物经代谢后毒性并无明显改变。肝脏功能极为复杂;从分子水平看肝细胞恰如一个发生着无数反应的宇宙。现已证实外源性化合物经代谢后可转变为极性更大的代谢产物,并排出体外;这些代谢酶主要存在于肝细胞的内质网中。内质网为细胞的亚微结构,是一种管状脂旦白网,有光面和粗面内质网之分,而代谢外源性化合物的酶活性主要集中在滑面内质网内,统称为肝微粒体药物代谢酶或肝微粒体酶或混合功能氧化酶 A variety of chemical and biological activity of different compounds can make the liver lesions. Most exogenous compounds, regardless of their toxicity, need to be metabolized (or biotransformed) in the body, in particular in the liver, and become metabolites of the same, which may be more or less toxic than the original compounds and in part may also cause deformities , Mutagenic and carcinogenic. However, there are also some compounds that show no significant changes in their metabolism after metabolism. Hepatic function is extremely complex; at the molecular level, hepatocytes resemble an innumerable universe of reactions. It has been confirmed that exogenous compounds can be metabolized into more polar metabolites and excreted; these metabolic enzymes are mainly found in the endoplasmic reticulum of hepatocytes. Endoplasmic reticulum is a submicroscopic structure of cells. It is a tubular lipid denatured mesh with smooth and rough endoplasmic reticulum, while the enzyme activity of metabolizing exogenous compounds is mainly concentrated in the smooth endoplasmic reticulum, Collectively referred to as liver microsomal drug metabolizing enzymes or liver microsomal enzymes or mixed-function oxidase