2. Findings
2.1. Male rat liver
Aromatase activity was determined in the liver of male rats exposed to alcohol in a liquid diet (36% of calories) for 34–54 days (Gordon et al., 1979). The activity was determined by incubating hepatic microsomes with tritium-labeled androstenedione or testosterone for 15 to 120 min, followed by measuring the rate of formation of tritium-labeled estrone or estradiol, respectively. The hepatic aromatase activity was significantly increased with the use of androstenedione or testosterone as a substrate in alcohol-treated rats, compared with findings in pair-fed controls. In addition, in alcohol-fed rats, plasma estradiol levels increased by 60% and concomitantly plasma testosterone levels decreased by 55%, an indicator of aromatization. However, plasma levels of androstenedione and estrone were not affected by alcohol consumption. Other investigators also observed increased hepatic aromatization of testosterone to estradiol in male rats exposed to alcohol in a liquid diet (36% of calories) for 5 months (Chung, 1990). Consistent with the increased aromatization, serum estradiol levels were increased and testosterone levels were decreased significantly in this study.