The Formation of N-Glucuronides Catalyzed by Purified Hepatic 17β-Hydroxysteroid and 3α-Hydroxysteroid UDP-Glucuronyltransferases
Conjugation of many endogenous and exogenous chemicals with glucuronic acid, catalyzed by UDP-glucuronyltransferases (EC 22.214.171.124), is an important step in their detoxification and elimination from the body. We have previously reported on the purification of three different UDP-glucuronyltransferases (UDPGTs) from hepatic microsomes of female Sprague-Dawley rats1. A 17β-hydroxysteroid UDPGT catalyzes the glucuronidation of the 17β-hydroxy position of steroids, such as testosterone and 17β-estradiol, and xenobiotics such as p-nitrophenol and 1-naphthol. A 3α-hydroxysteroid UDPGT has been purified which is specific for the glucuronidation of the 3α-position of steroids and bile acids2,3. A 3-methylcholanthreneinducible form of p-nitrophenol UDPGT catalyzes the conjugation of various xenobiotic substrates, such as p-nitrophenol, 4-methylumbelliferone and 1-naphthol, with glucuronic acid1.
KeywordsTestosterone Androgen Biphenyl Phosphatidylcholine Phenobarbital
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