In Vivo Suppression of Bisphenol A on Estradiol 2- and 4-Hydroxylase Activities in Hepatic Microsomal Fractions of Male and Female Sprague-Dawley Rats

Abstract

This work was conducted to investigate the effect of bisphenol A (BPA) on estradiol (E2) 2-and 4-hydroxylase activities in the liver, kidney and lung tissues of male and female rats. After intraperitoneal administration of BPA to male and female rats for 4 days at 0, 10, and 50 mg/kg, the conversion of the substrate for hepatic and extra-hepatic enzyme activities was measured by GC/MSD. The result showed decreases of body and organ weights at 50 mg/kg BPA of male and female rats. Male hepatic E2 2-hydroxylase activity was inhibited by 68% at 10 mg/kg and by 82% at 50 mg/kg BPA. Female hepatic E2 2-hydroxylase activity was decreased by 46% at 10 mg/kg and by 56% at 50 mg/kg to the control. E2 4-hydroxylase was inhibited by 57 and 57% at 10 mg/kg and 54 and 78% at 50 mg/kg in liver of female and male, respectively. The urinary excretion rate of 2-hydroxyestradiol (2-OHE), androsterone and testosterone in urine of female rats with 50 mg/kg BPA were decreased significantly. The results showed that 50 mg/kg BPA was decreased E2 2-and 4-hydroxylase activities in liver, but not in other tissues. The urinary excretion rates of 2-OHE, androsterone and testosterone were also decreased. In liver, estrogenic enzyme activity were higher in male than female. These results suggest that BPA can disrupt estrogen metabolism by suppressing E2 2-and 4-hydroxylase activities in the liver of male and female rats.