An improved assay for steroid glucuronyltransferase in rat liver microsomes

✍ Scribed by Govind S. Rao; Gudrun Haueter; Marie Luise Rao; Heinz Breuer

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 416 KB
• Volume: 74
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(76)90307-9

✦ Synopsis

A simple and economical method of assaying rat liver microsomal estrone and testosterone glucuronyltransferase activity has been developed. Liver microsomes were activated by pretreatment with Lubrol WX. The incubation was carried out at 37°C for 30 min and contained 30-600 PM steroid, l-2 mM UDP-glucuronic acid, 10 mM MgC&, and 80-150 pg of microsomal protein. Enzyme activities showed a maximum at pH 8.8 with Tris-HCI buffer. After incubation the unreacted substrate was quantitatively removed by a single extraction with dichloromethane. The glucuronide was estimated by counting an aliquot of the aqueous phase in a liquid scintillation counter. The variation coefficients with estrone and testosterone as substrates were 6.0 and 4.0%, respectively.