title: Sex and strain differences in mouse hepatic microsomal coumarin 7-hydroxylase activity.
abstract: 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.
authors.affiliation: BIBRA Toxicology International, Carshalton, Surrey, UK.
authors.forename: M
authors.initials: M
authors.lastname: van Iersel
authors.forename: D G
authors.initials: DG
authors.lastname: Walters
authors.forename: R J
authors.initials: RJ
authors.lastname: Price
authors.forename: D P
authors.initials: DP
authors.lastname: Lovell
authors.forename: B G
authors.initials: BG
authors.lastname: Lake
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D065637:Cytochrome P-450 CYP2A6; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D005260:Female; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D012727:Sex Characteristics; D013045:Species Specificity
chemical_list: D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585520:Cyp2a5 protein, mouse; D065637:Cytochrome P-450 CYP2A6; D000072467:Cytochrome P450 Family 2