Organ specificity of the sex dependent regulation of aryl hydrocarbon hydroxylase (AHH) in rat

Aryl hydrocarbon hydroxylase (AHH) activity was measured in liver, kidneys and lungs of control and gonadectomized Sprague-Dawley rats. There was a six-fold difference in hepatic AHH activity between male and female rat. Activity in male was highest, castration reduced this activity by about 50%, whereas ovariectomy had little effect on activity in female. No sex difference in lung AHH activity was discernable; on the other hand kidney AHH activity was higher in females than in males. These data suggest that, at least in the rat, sex dependent regulation of microsomal mixed function oxygenases is organ specific.