Abstract
Uridine diphosphate glucuronate glucuronyltransferase (UDPGT) activity was measured in hepatic microsomes with 14C-estrone and 17β-14C-estradiol as substrates. The apparent Km values for the conjugation of estrone and estradiol by rat liver microsomes were 1.78 ± 0.56 x 10-5 M and 2.53 ± 0.94 x 10-5 M, respectively (mean of 20 determinations ± SD). The conjugation of estrogens was inhibited by morphine, p-hydroxyamphetamine, SKF 525-A, and both the demethylated and hydroxylated metabolites of chlorpromazine. Phenobarbital, 3-methylcholanthrene, and 3,4-benzpyrene increased the conjugation of the estrogens per g of liver but not the specific activity of UDPGT (nanomoles per mg of microsomal protein). Pretreatment of rats with morphine, chlorpromazine, and amphetamine increased the specific activity of the transferase for the conjugation of estrogens.
Footnotes
- Received July 19, 1974.
- Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$25.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.
In this issue
THE INTERACTION OF FOREIGN CHEMICAL COMPOUNDS WITH THE GLUCURONIDATION OF ESTROGENS IN VITRO
