Strain Differences in Aryl Hydrocarbon Hydroxylase Induction by 3-Methylcholanthrene in Rabbits

Abstract

Summary

We determined both basal and induced AHH activity in livers of six partially inbred strains of rabbits. Strain III rabbits had the highest enzyme activity upon induction by 3-MCA, i.e., four to five times that in strain WH (noninducible), which has the lowest enzyme activity. AHH induction was also “low” in strains X, OS, ACEP, and AC. F₁ hybrids between strains III and WH revealed a differential response to the induction of liver AHH activity by MCA: the levels of induced hydroxylase activity were consistently higher in (III X WH)F₁ rabbits than in the reciprocal (WH X III)F₁ hybrids. All possible crosses between these two “extreme” strains are now being analyzed to estimate the number of genes involved in their response difference to MCA.

This work was supported in part by a grant from the Council for Tobacco Research, USA, research contract N01 CP 33255 within the Special Virus Cancer Program of the National Cancer Institute, NIH Research Grant RR 00251 from the Division of Research Facilities and Resources, and by an allocation from NIH General Research Support Grant RR 05545 from the Division of Research Resources to the Jackson Laboratory. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory Animal Care.