Abstract: Objective To observe the effects of differentiod ine intake on the dirtribution and expression of sodium/iodide symporter(NIS)prote in in rats with tissue microarray.Methods Wistar rats were randomly divided into three groups:low idoine(LI),normal iodine(NI)and high idoine(HI)based on the iodine levels of the diet.Three months later,urinary iod ine wasm easured and tissue microarray conta ining 48 spots of rattissue was prepared.Immmnohisto chemistry method was used to detect the distribution and expression of NIS prote in in different tissues.Results Compared with NI group,urinary iodine was considerably lower in LI group and higher in HI group,paralleling to the iriodine in takes.On the other hand,the different iodine intake induced changes of NIS expression in some tissues.The expression of NIS in thy roid follicuar epithelial cells was significantly higher in LI group than in NI and HI groups.On the contrary,NIS loacting at renal tubular epithelial cells in HI group streng thened obviously.NIS also distributed in gastric muco sa,in testina lmucosa,glandula ang ularis and ovaries with no obvious difference among the three groups.Conclusion The findings reveal that there are different expressions of NIS in several tissues of rats.Different iodine intake can cause changes of NIS expression in tissues,especially in thyrid and kidney.