OBJECTIVETo detect the effect of deltamethrin (DM) on benzyloxyresorufin O-dealkylatase (BROD) activity and the expression of CYP2B1/2B2 in rat brain.

METHODSBROD activity was determined by fluorophotometry under the treatment of DM in vivo and vitro. Western-blot analysis was used to detect the expression of CYP2B1/2B2.

RESULTSIn vivo, DM could markedly inhibit BROD activity in rat brain microsome after rats had been treated with DM (12.5 mg.kg-1.d-1, i.p.) for 5 days. The inhibitory rate in whole brain, cerebral cortex and cerebellum were 26.7%, 23.8% and 33.3% respectively(P < 0.05). However, in vitro, under the concentration of 2 x 10(-8)-2 x 10(-4) mol/L of DM, there was no obvious change of BROD activity in rat brain. Moreover, Western-blot analysis indicated that DM could significantly reduce the expression of CYP2B1/2B2 in vivo, the inhibitory rate of protein synthesis was 42.6%.

CONCLUSIONDM could inhibit BROD activity in rat brain and this effect may be related to the reduction of CYP2B1/2B2 protein synthesis.

Animals ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; biosynthesis ; Blotting, Western ; Brain ; drug effects ; enzymology ; Cytochrome P-450 CYP2B1 ; antagonists & inhibitors ; biosynthesis ; Enzyme Inhibitors ; toxicity ; Insecticides ; toxicity ; Nitriles ; toxicity ; Pyrethrins ; toxicity ; Rats ; Steroid Hydroxylases ; antagonists & inhibitors ; biosynthesis