Abstract: Objective To observe the effects of prenatal exposure to lowlevel lead on the protein and mR NA expression of glial fibrillary acidic protein(GFA P)in hippocampus of rat's offspring,and to explore the molecular mechanisms of lead on learning and memory.Methods The pregnant rats were rando mizedly divided into 4 groups and pr ovided with doubly evaporated water in contro l groups and 125,250,500 mg/L lead acetate solution via drinking water in treatment groups respectively dur ing pregnancy.The GFA P protein and mRN A expression athippocampal CA1 region were obser ved by immunohistochemistry and in situ hybridization.Results The cell numbers of GFA P protein and mRNA positive expression at 1-day and 21-day old offsprings in treatment group were sig nificantly higher than that of control(P<0.05),but no significant difference at 60-day old offsprings.Conclusion Prenatal exposure to lowlevel lead could promote the GFAP= protein and mRNA ex pression athippocampal CA1 region,which maybe is one of the molecular mechanisms of lead on learning and memory.