{'fraction_non_alphanumeric': 0.04904306220095694, 'fraction_numerical': 0.02631578947368421, 'mean_word_length': 5.828571428571428, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Involvement of P450 1A1 in benzo(a)pyrene but not in benzo(a)pyrene-7,8-dihydrodiol activation by 3-methylcholanthrene-induced mouse liver microsomes.

Synchronous fluorescence spectrophotometry for benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE)-DNA adducts was used to study the activation pathway of benzo(a)pyrene in C57BL/6 mice. Benzo(a)pyrene but not benzo(a)pyrene-7,8-diol activation by 3-methylcholanthrene-induced mouse liver microsomes was inhibited by a monoclonal antibody (Mab 1-7-1) against CYP1A1/2 suggesting that 1A1 probably takes part in the first P450 reaction. However, aryl hydrocarbon hydroxylase activity, a classical measure of benzo(a)pyrene metabolism, was not inhibited by the same concentration of Mab 1-7-1. None of the other antibodies used, detecting 2A, 2B, 2C or 2E subfamilies, inhibited the adduct formation. Troleandomycin and gestodene, chemical inhibitors of human 3A4, inhibited benzo(a)pyrene-7,8-diol activation by 3-methylcholanthrene-induced microsomes to some extent only in high concentrations. Although liver microsomes from 3-methylcholanthrene-induced mice catalyzed the formation of BPDE-DNA in vitro clearly more than uninduced microsomes, 3-methylcholanthrene pretreatment in vivo decreased the adduct formation in benzo(a)pyrene-treated mice. These results emphasize the significance of detoxicating and DNA-repairing pathways in vivo. Finally, synchronous fluorescence spectrophotometry for BPDE-DNA measures the end-point of the three-step activation pathway while aryl hydrocarbon hydroxylase measures a one-step hydroxylation. Thus, these methods should be used rather as corroborative than mutually exclusive assays.