Abstract： Objective To observe the changes of sodium iodide symporter (NIS), thyrotropin receptor (TSHR) mRNA and protein expression in diabetes mellitus(DM) rats as well as the intervention effects of aminogua-nidine and insulin, and to observe the damage effects of hyperglycemia toxicity on throid gland and the possible mechanisms. Methods Forty-nine rats were fed with high lipid feedstuff and intravenous injected with streptozocin to establish DM rat model and then were divided into DM group(n=17),aminoguanidine intervention group(n= 16) and insulin intervention group(n=16), meanwhile 9 rats were taken as controls. At the 12th weekend, rats were sacrificed and thyroid gland was taken to detect NIS and TSHRmRNA expression with RT-PCR skills and West-ern Blotting skills. Results NISmRNA and protein expression in thyroid glands of DM rats were much lower than those in NC group, while TSHRmRNA and protein expression were much higher than those in NC group(P<0.05). TSHRmRNA and protein expression after either aminoguanidine or insulin intervention were lower than those in DM group(P<0.05), but NISmRNA and protein expression were higher than those in DM group rats (P<0.05). Conclusion Hyperglycemia toxicity may lead to the decrease of NIS expression and increase of TSHR expression in thyroid gland of DM rats through protein nonenzymic glycation pathway.