Hepatic microsomal drug oxidation and electron transport in newborn infants

J Pediatr. 1974 Oct;85(4):534-42. doi: 10.1016/s0022-3476(74)80465-8.


Many drugs require oxidative metabolism for termination of action and/or for elimination from the body. Many oxidative reactions are catalyzed by hepatic microsomal enzymes. The activities of various drug-metabolizing enzymes, namely, NADPH cytochrome c reductase, NADPH oxidase, aminopyrine-N-demethylase, and analine P-hydroxylase, and the content of cytochrome P-450, were measured in hepatic microsomes obtained from seven newborn infants and four adult patients. The results in the newborn infant show increasing activities of these enzymes (except aminopyrine-N-demethylase) related to advancing age. Good correlation between three components of the hepatic microsomal mixed function oxidase system and aniline p-hydroxylase was established, whereas only NADPH oxidation correlated with aminopyrine N-demethylation. The rate of substrate or drug oxidation and the activities of the components of the microsomal electron transport pathway were lower than comparable values in the adult. The data demonstrate a possible biochemical basis for the transient deficiency in drug metabolism seen in newborn infants.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Factors
  • Aminopyrine N-Demethylase / metabolism
  • Aniline Compounds
  • Autopsy
  • Biopsy
  • Cytochrome P-450 Enzyme System / metabolism
  • Cytochrome Reductases / metabolism
  • Electron Transport
  • Female
  • Gestational Age
  • Humans
  • Infant, Newborn*
  • Infant, Premature*
  • Male
  • Microsomes, Liver / enzymology
  • Microsomes, Liver / metabolism*
  • Middle Aged
  • Mixed Function Oxygenases / metabolism
  • NADH, NADPH Oxidoreductases / metabolism
  • Oxidation-Reduction
  • Pharmaceutical Preparations / metabolism*
  • Pregnancy


  • Aniline Compounds
  • Pharmaceutical Preparations
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Aminopyrine N-Demethylase
  • NADH, NADPH Oxidoreductases
  • Cytochrome Reductases