Cytochrome P450-mediated 17b-estradiol metabolism in zebrafish L

on, am, cm protein was verified using carbon monoxide difference spectra 2 2 results suggest that fish CYP1A and CYP1C proteins are zebrafish (Danio rerio) have a single CYP3A gene, CYP3A65 the single CYP1B gene found in all vertebrate lineages. 2001). The regioselective hydroxylation of E2 by purified formation (Lee et al. 2003). On the other hand, E2 317Journal of Endocrinology (2010) 206, 317–325CYP1Cs are found in all non-mammalian vertebrate lineages (Goldstone et al. 2007). Fish have CYP1C1 and CYP1C2 metabolism by mammalian CYP1B1 produces similar amounts of 4-OHE2 to CYP1As and CYP3As, but very DOI: 10.1677/JOE-10-0075(Qiu et al. 2008). The CYP1 family contains more subfamilies in non-mammalian vertebrates. There are two CYP1A genes (CYP1A1 and CYP1A2) in mammals, and a single CYP1A gene in fish, with the exception of some polyploid species such as the salmonids (Goldstone et al. 2007). CYP1B1 is CYPs has been well studied in mammals (Lee et al. 2003). CYP1A1, CYP1A2, and CYP3A4 show the highest rates of metabolism in humans, mostly as a result of high 2-hydroxylation activity (Lee et al. 2003). Consequently, these three CYPs have very low ratios of 4-OHE2 to 2-OHE2families across vertebrates. The CYP3A subfamily includes multiple genes in mammals; humans have four CYP3As (Qiu et al. 2008). Most fish contain only one or two CYP3As; 2-hydroxyE2 (2-OHE2) metabolite, with limited production of 4-hydroxyE2 (4-OHE2) and small levels of metabolites hydroxylated at either the 6b, 16b, or 16a positions (Lee et al.resorufin and 7-benzyloxy-4-(trifluoromethyl)-coumarin. Rates of in vitro E2 metabolism into 4-hydroxyE2 (4-OHE2), 2-hydroxyE2 (2-OHE2), and 16a-hydroxyE1 (16a-OHE1) metabolites were determined by gas chromatography/mass spectrometry. The 2-OHE2 metabolite was produced by al