Acute arsenic treatment alters cytochrome P450 expression and arachidonic acid metabolism in lung, liver and kidney of C57Bl/6 mice

1. Arsenic (As(III)) toxicity has received increasing attention as human exposure to arsenic is associated with pulmonary, hepatic and renal toxicities. Therefore, in the present study, we investigated the effect of acute As(III) treatment on pulmonary, hepatic and renal cytochrome (CYP) P450-mediated arachidonic acid metabolism. 2. Our results demonstrated that acute As(III) treatment (12.5 mg/kg) altered CYP epoxygenases, CYP omega-hydroxylases and EPHX2 mRNA levels that were isozyme and tissue specific. 3. Furthermore, As(III) increased the formation of epoxyeicosatrienoic acids (EETs) in the kidney without affecting their levels in the lung or liver. In addition, acute As(III) treatment increased dihydroxyeicosatrienoic acid (DHETs) formation in the lung, while it did not affect liver DHETs formation and decreased kidney DHETs formation. 4. As(III) also increased total epoxygenases activity in the lung while it decreased its levels in the kidney and had no effect on the liver. Furthermore, As(III) increased 20-hydroxyeicosatetraenoic acid formation in the liver while it decreased its formation in the kidney. 5. Lastly, As(III) increased soluble epoxide hydrolase activity in the lung, while it decreased its levels in the kidney and had no effect on the liver. In conclusion, this is the first demonstration that As(III) alters arachidonic acid metabolism in a tissue specific manner.