Steroids in Germfree and Conventional Rats: Sulpho‐ and Glucuronohydrolase Activities of Caecal Contents from Conventional Rats

Caecal contents from conventional rats has been shown to have steroid sulphatase and glucuronidase activities. Whereas the sulphatase activity was of microbial origin the glucuronidase activity was also present in caecal contents from germfree rats. In vitro incubations showed that sulphuric acid esters of the 3α‐, 3β‐, 17β‐ and 21‐hydroxyl groups were all hydrolyzed by the caecal bacteria. The ration between free and conjugated metabolites of [4‐¹⁴C]corticosterone administered to germfree and conventional rats was much higher in the conventional than in the germfree rats. This shows that microbial hydrolysis of steroid sulphates takes place also in vivo.