Preferential Overexpression of a Class MU GlutathioneS-Transferase Subunit in Mouse Liver by Myristicin

Abstract

The present studies were undertaken to elucidate the mechanism of induction of glutathione S-transferase (GST) in mouse liver by myristicin, an active constituent of parsley leaf. A/J albino mice, given 5 to 50 mg doses of myristicin, showed 4- to 14-fold increase in liver GST specific activity over the control. GST purified from equal amounts of control and myristicin-treated livers indicated a marked increase in the GST activity. A relatively higher increase in GST activity towards 2,4-dichloronitrobenzene and a profound increase in the levels of GST μ on Western blot analysis of the myristicin-treated mouse liver suggest a preferential induction of GST μ. Results of the study also indicate that out of the two μ class GST subunits (Mr. 26,500 and Mr. 25,000) expressed in liver only one (Mr. 26,500) is significantly elevated. Myristicin treatment caused a slight change in the GST π levels while the levels of GST α showed a modest increase. These results suggest that myristicin could be an effective chemopreventive agent, particularly for carcinogens that are detoxified by the μ class GST.