title: Circannual variation and genetic regulation of hepatic testosterone hydroxylase activities in inbred strains of mice.
abstract: Hydroxylation of testosterone by hepatic microsomes at positions 6 alpha, 6 beta, 7 alpha, 15 alpha, and 16 alpha has been studied in C57BL/6J, 129/J, and A/J mice. Differences in hydroxylase activities between the C57BL/6J and A/J strains and between the C57BL/6J and 129/J strains were investigated using standard genetic breeding protocols. In the C57BL/6J X A/J line, 6 alpha- and 7 alpha-hydroxylase activity appeared to be under polygenic control in both sexes, as did 15 alpha-hydroxylase activity in females. The lack of 16 alpha-hydroxylase activity observed in 129/J females behaved as a recessive, autosomal, single locus, sex-limited trait. In several instances, the level of hydroxylase activity at one position appeared to be affected by the level of hydroxylase activity at a second position; however, no clear-cut pattern was discerned. Over a period of a year, a remarkable cycle in total hydroxylase activity for all mice was observed; the average activity was greatest in December and least in April.
mesh_terms: D000818:Animals; D005260:Female; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010507:Periodicity; D012737:Sex Factors; D013045:Species Specificity; D039181:Steroid 16-alpha-Hydroxylase; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism*; D013739:Testosterone
chemical_list: D013739:Testosterone; D013250:Steroid Hydroxylases; D039181:Steroid 16-alpha-Hydroxylase