Sex-dependent differences in phenobarbitone-induced oestradiol-2-hydroxylase activity in rat liver
Date
1981
Journal Title
Journal ISSN
Volume Title
Publisher
Health & Medical Publishing Group
Abstract
Oestradiol-2-hydroxylase (E2-OH) activity was measured in liver and brain microsomes of 6-8-week-old Wistar rats. Phenobarbitone (75 mg/kg daily for 3 days) significantly increased enzyme activity in the liver of males and females, but there were striking differences between the two sexes. In males the enzyme activity was increased by 37% over control values and in females by 200%. The total microsomal cytochrome P-450 content was increased by 75% in males and by 82% in females. The apparent Michaelis constant (Km) of E2-OH for 17β-oestradiol in untreated males (9.8 μM) and females (9.2 μM) did not differ significantly. Phenobarbitone treatment, however, tended to reduce the apparent Km in males (8.2 μM) and to increase it in females (18.7 μM). E2-OH activity was also detected in brain tissue of both sexes, but it was 50-200-fold lower than in the liver and was not increased by phenobarbitone.
Description
CITATION: Theron, C. N., Neethling, A. C. & Taljaard, J. J. F. 1981. Sex-dependent differences in phenobarbitone-induced oestradiol-2-hydroxylase activity in rat liver. South African Medical Journal, 60:279-282.
The original publication is available at http://www.samj.org.za
The original publication is available at http://www.samj.org.za
Keywords
Estradiol