Effect of sex hormones on rat liver cytosolic alcohol dehydrogenase activity

Rat liver cytosolic alcohol dehydrogenase (ADH) activity is known to be significantly higher in females than in males. To elucidate a possible mechanism of sex difference in the ADH activities, we studied the in vivo effects of the administrations of β-estradiol, progesterone or testosterone, and castrations (orchiectomy and ovariectomy) on the ADH activities in male and female Sprague-Dawley adult rats. Furthermore, we studied the ADH activities in six liver portions of sham-operated male, orchiectomized male, and female rats. The ADH activities were higher in orchiectomized male rats than in sham-operated male rats. These results were observed in all liver portions. The administration of testosterone (5 mg/kg BW, twice a day for 7 d) to orchiectomized male rats significantly decreased ADH activities. The ADH activities in ovariectomized female rats were comparable with those in sham-operated female rats. The administration of β-estradiol (50 μg/kg BW, once every 2 d for 20 d) or progesterone (75 μg/kg BW, once every 2 d for 20 d) to rats increased the ADH activities in males more than in females. These results suggest that the inhibitory action of androgen and the slight facilitatory actions of progestin and estrogen are involved in the mechanism of sex difference in adult rat liver cytosolic ADH activity.