Previous studies have suggested that glutathione-S-transferase π (GST-π) over-expression in the brain tissue is associated with refractory epilepsy.However,whether the change in GST-π level in the peripheral blood is in line with that in brain tissue remains unknown.This study examined the correlation between GST-π in brain tissue and that in peripheral blood in rat models of pilocarpine-induced refractory epilepsy.The animals were divided into drug-resistant group and drug-responsive group according to the response to anti-epileptic drugs.GST-π expression in brain tissue was immunohistochemically determined,while the expression of GST-π in peripheral blood was analyzed by Western blotting.In the hippocampus and cortex,GST-π was mainly found in the cytoplasm and membrane of neurons,and the GST-π expression level was higher in drug-resistant group than in the drug-responsive group and saline control group (P＜0.05).Moreover,there was no significant difference between responders and saline control animals (P＞0.05).The change in expression of GST-π in peripheral blood showed the same pattern as that in brain tissues,suggesting GST-π might contribute to drug resistance in epilepsy.Importantly,the GST-π over-expression in peripheral blood could be used as a marker for resistance to anti-epileptic agents.