Induction of Cytochrome P450 1A by β-naphto-flavon within the Pig Liver and Central Nervous System

The cytochromes P450 play a key role in the metabolism of both endogenous compounds such as steroids, cytokines, fatty acids, D vitamins, and xenobiotics including drugs and environmental contaminants. The purpose of this work was to investigate the expression and the induction of CYP1A within brain regions and the liver of pigs after treatment with β-naphtoflavon. The CYP1A family is predominant in the detoxification of aromatic hydrocarbons (PAH) (Waxman, 1999), and of some dioxins such as 2,3,7,8-tetrachloro-dibenzop-dioxin (2,3,7,8-TCDD) (Clemons et al., 1998), as well as in the activation of aflatoxin B1, and of benzo-a-pyrhene (Omiecinski et al., 1999). Several substrates such as dioxin-like polychlorinated biphenyls (PCBs), are able to induce CYP1A1, CYP1A2 and CYP1B1 by the activation of the AhR receptor; whereas, other compounds, like fluoroquinolones, can inhibit the activity of CYP1A. In fish, the induction of CYP1A has been characterised as a biological indicator of environmental contamination (Arinc et al., 2000). Furthermore, correlations between exposure to environmental pollution and reproductive dysfunction and tumours have been reported in several marine mammals (Beland et al., 1993); CYP1A is always involved in the production of highly reactive and toxic metabolites. Recently, in the central nervous system (CNS) of several animal species (human, rat, trout, sea bass, salmon, gilt-bream and rabbit) the presence of CYP1A has been demonstrated by RT-PCR methods, as well as its induction by 3-methylcholanthrene, phenobarbital and BNF (Dayal et al., 2001; Liu et al., 2001; Ortiz-Delgado et al., 2002; Chung-Davidson et al., 2004).