Modulation of cytochrome P450 isozymes in human liver, by ethanol and drug intake.

Cytochromes P450 (P450) are a family of isozymes which play an important role in xenobiotic metabolism. The concentration of three P450 isozymes, namely P450-IIE1(A1c),-IIIA(NF) and -IIC8-10(MP) has been measured in human liver biopsies of patients with different alcohol and drug intake status. All these three P450s were expressed in all subjects. Ethanol intake increased P450-IIE1(A1c) content with no effect on the content of the two other P450s. Drug intake (barbiturates) increased both P450-IIIA(NF) and -IIC8-10(MP) content without any effect on P450-IIE1(A1c). This paper brought, at protein level, further evidence of the importance of environmental conditions on P450 isozyme pattern, and therefore, on drug metabolizing capacity of human liver.