title: Cytochrome P-450 and chromosome damage by cyclophosphamide in LEC strain rats predisposed to hereditary hepatitis and liver cancer.
abstract: LEC strain rats predisposed to hereditary hepatitis and liver cancer were examined for hepatic drug-metabolizing ability and the inducibility of chromosome damage by cyclophosphamide (CP) in somatic cells. Whereas the hepatic cytochrome P-450 contents and the activities of cytochrome P-450-catalyzed monooxygenases were lower in females than in males of both LEC and control LEA strains, male LEC rats exhibited significantly reduced cytochrome P-450 contents and monooxygenase activities compared with male LEA rats. When exposed to CP, a promutagen/procarcinogen requiring P-450-dependent metabolic activation, the frequencies of chromosome aberrations and sister-chromatid exchanges (SCEs) in bone marrow cells tended to be lower in females than in males of each strain and lower in LEC than in LEA rats of the same sex. In particular, the CP-induced SCEs were substantially lower in LEC rats. However, no such sex and strain differences were found in the SCE frequencies in regenerating hepatocytes of partially hepatectomized rats exposed to CP.
authors.affiliation: Chromosome Research Unit, Faculty of Science, Hokkaido University, Sapporo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Masuda
authors.forename: S
authors.initials: S
authors.lastname: Abe
authors.forename: M C
authors.initials: MC
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Sugiyama
authors.forename: N
authors.initials: N
authors.lastname: Taniguchi
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D002869:Chromosome Aberrations; D003520:Cyclophosphamide / Q000633:toxicity*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004198:Disease Susceptibility; D005260:Female; D006520:Hepatitis, Animal / Q000235:genetics; D008099:Liver / Q000201:enzymology*; D008113:Liver Neoplasms / Q000235:genetics; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D011922:Rats, Mutant Strains; D012727:Sex Characteristics; D012854:Sister Chromatid Exchange; D013250:Steroid Hydroxylases / Q000378:metabolism
chemical_list: D003520:Cyclophosphamide; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases