Effect of the mouse mutants testicular feminization and sex reversal on hormone-mediated induction and repression of enzymes.
The mouse mutants testicular feminization and sex reversal have been used to investigate hormone-mediated induction and repression of enzymes. Tfm/Y animals were already known to be androgen insensitive, rendering the androgen-inducible enzymes ADH and beta-glucuronidase noninducible because of an inherited deficiency of a cytosol androgen-receptor complex. The animals display female secondary sexual characteristics. Sxr/+,XX animals display male primary and secondary sexual characteristics with small testes. We demonstrate (1) that the Tfm mutation is pleiotropic, preventing repression of an androgen-repressible enzyme (ornithine aminotransferase) as well as induction of androgen-inducible enzymes, (2) that an estrogen-inducible enzyme (histidine decarboxylase) is not affected by the Tfm mutation, and (3) that Sxr/+,XX animals produce enough androgen for malelike activities of androgen-sensitive enzymes. It was also discovered that histidine decarboxylase repressed by androgen in normal animals, rather than being unaffected by it in Tfm/Y animals, is in fact induced. This unexpected phenomenon is discussed and an explanation is suggested for it.
D000429:Alcohol Oxidoreductases / Q000378:metabolism; D013734:Androgen-Insensitivity Syndrome / Q000201:enzymology*; D000818:Animals; D013196:Dihydrotestosterone / Q000494:pharmacology*; D012734:Disorders of Sex Development; D004790:Enzyme Induction / Q000187:drug effects*; D004794:Enzyme Repression / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005838:Genotype; D005966:Glucuronidase / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D006638:Histidine Ammonia-Lyase / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D051379:Mice; D009953:Ornithine-Oxo-Acid Transaminase / Q000378:metabolism; D010641:Phenotype; D014559:Urocanate Hydratase / Q000378:metabolism
D013196:Dihydrotestosterone; D004958:Estradiol; D000429:Alcohol Oxidoreductases; D009953:Ornithine-Oxo-Acid Transaminase; D006593:Hexokinase; D005966:Glucuronidase; D014559:Urocanate Hydratase; D006638:Histidine Ammonia-Lyase