Abstract: 　AIM: To observe the effect of artemether (Art) on nucleoside uptake and nucleic acid content in Schistosoma japonicum . METHODS: RNA and DNA contents of both male and female worms harbored in mice treated intragastrically (ig) with Art 300 mg/kg for 24 h or 48 h were determined, respectively. After in vivo drug treatment , the schistosomes recovered were in vitro maintained in drug-free medium containing [ 3H]adenosine, [5- 3H] uridine or [methyl- 3H]thymidine at a final concentration of 37 MBq/L or 74 MBq/L for 2 h or 4 h, the tritiated nucleoside uptake and incorporation into nucleic acid of schistosomes were measured. RESULTS: The RNA and DNA contents of female worms recovered from the host 48 h after dosing were markedly decreased by 51.6% and 23.5%, respectively,while the RNA content of male worms showed 42.4% reduction. When the above-mentioned schistosomes were in vitro exposed to the tritiated nucleoside for 2 h or 4 h, apparent decrease in tritiated nucleoside uptake with reduction rates of 35.2%～50.1% was seen in female worms. The incorporation of [methyl- 3H]thymidine into the female worm DNA 2 h after incubation was reduced by 71.4% while the incorporation of [ 3H]adenosine into the female worm RNA and DNA 4 h after incubation was reduced by 65.2% and 50.0%,respectively. CONCLUSION: Art exhibited an apparent effect on the nucleic acid metabolism in schistosomes, especially in female worms.

Key words: Schistosoma japonicum, nucleic acid, tritiated nucleoside, artemether