[Covalent fixation in vivo of trenbolone acetate and estradiol to hepatic DNA of the rat: comparative study of the fixation of tritiated molecules and post labeling with radiophosphorus].

In vivo covalent binding of trenbolone and estradiol was assayed using either radiolabeled compounds or 32P-post labeling. The covalent binding index, as measured with tritiated molecules, was 2.4 for the alpha isomer of trenbolone, 5.4 for its beta isomer and 5.4 for 17-beta estradiol. Using 32P-post labeling at repeated medium doses or a single high dose did not allow any of the 3 compounds to reveal specific adducts in the background of adducts spontaneously formed in control animals. It can therefore be concluded that these steroids most probably do not have a direct genotoxic action.