Sex and strain differences in mouse hepatic microsomal coumarin 7-hydroxylase activity

Food Chem Toxicol. 1994 Apr;32(4):387-90. doi: 10.1016/0278-6915(94)90078-7.


Hepatic microsomal coumarin 7-hydroxylase activity has been determined in male and female mice of strains A/J, AKR, BALB/c, CBA/Ca, C3H/He, C57BL/6J, DBA/2 and 129. In males, coumarin 7-hydroxylase activity was highest in liver microsomes from DBA/2 mice and lowest in BALB/c mice. With female mice enzyme activity was highest in DBA/2 and 129 strains, intermediate in the CBA/Ca strain and comparatively low in the other five strains. Marked sex differences were observed in coumarin 7-hydroxylase activity with enzyme activity in female animals from strains DBA/2, 129 and CBA/Ca being 4.8-, 6.2- and 4.8-fold higher, respectively, than in male mice. In contrast, only minor sex and strain differences in levels of total microsomal cytochrome P-450 were observed. These results demonstrate marked sex and strain differences in mouse hepatic microsomal coumarin 7-hydroxylase activity. Such differences may be due to variations in particular cytochrome P-450 isoenzymes such as CYP2A5, not all of which can be explained by the known allelic difference in the Cyp2a-5 locus.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aryl Hydrocarbon Hydroxylases*
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 Enzyme System / metabolism*
  • Cytochrome P450 Family 2
  • Female
  • Male
  • Mice
  • Mice, Inbred A
  • Mice, Inbred AKR
  • Mice, Inbred BALB C
  • Mice, Inbred C3H
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Mice, Inbred DBA
  • Microsomes, Liver / enzymology*
  • Mixed Function Oxygenases / metabolism*
  • Sex Characteristics*
  • Species Specificity


  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Aryl Hydrocarbon Hydroxylases
  • Cyp2a5 protein, mouse
  • Cytochrome P-450 CYP2A6
  • Cytochrome P450 Family 2