Abstract: Objective To explore the proper dosage of streptozotocin (STZ) in the hyperglycemic models in the Mongolian gerbils induced by STZ. Methods The forty Mongolian gerbils were divided randomly into normal control group: A group intraperitoneally (i.p.) injected with acid citrate buffer solution and hyperglycemic groups: B、C、D、E、F group i.p. injected with STZ at the dose of 150、200、250、400、600 mg/kg body weight, respectively. The levels of blood glucose, the body weights and 24 h urine volume in two months were tested accordingly. Result Twenty-four hours after STZ injection, blood glucose concentration of the gerbils in C and D group are more than 16.65 mmol/L and shortly decreased at no less than 16.65 mmol/L since 72 hours after STZ injection, in the following 4 days，blood glucose rose up to 25 mmol/L，the nonfasting blood glucose level became relatively stable since 7 days after STZ injection in Mongolian gerbils, which were kept under observation for 2 months. These hypeiglycemic Mongolian gerbils in C group and D group which had higher achievement ratio, lower mortality and lower rate of spontaneous recovery had distict diabetic symptoms (Polyuria, polydipsia, hyperphagia and weight loss) with hyperglycemia during the experiment period. Seven days aller STZ injection, the achievement ratio of gerbils in B group was 62.5%(5/8) and the maintenance rate of hyperglycemia during the experiment period was 25%(2/8). The mortality of gerbils in E and F group were 83.30%(5/6) and 100% since 7 days after STZ injection. Conclusion The stable hyperglycemic models in the Mongolian gerbils can be induced by large dose of streptozotocin once?the standard of hyperglycemic model in the Mongolian gerbils is that either the fasting blood glucose or nonfasting blood glucose is above 16.65 mmol/L, the proper dosage of streptozotocin (STZ) may be between 200 mg/kg and 250 mg/kg.

Key words: Streptozotocin, Mongolian gerbils, Hyperglycemic models, Dosage