Objective   To explore the difference of male and female rats in establishing diabetic model by feeding lardy diet and intraperitoneally injecting a low dose streptozotocin (STZ).     Methods   Totally 184 male and female Wistar rats (each 92 rats) were induced to diabetes mellitus by feeding lardy diet and intraperitoneally injecting 25 mg/kg STZ for 5 weeks. For the 114 left living rats (70 females and 44 males)

they were randomized into female high rosiglitazone group (

n

=23)

male high rosiglitazone group (

n

=15)

fe

male low rosiglitazone group (

n

=23)

male low rosiglitazone group (

n

=15)

female model group (

n

=24)

and male model group (

n

=14). Rosiglitazone at 2 or 0.5 mg/kg were intragastrically administered to corresponding rats once a day for 4 weeks. Another 8 health female and 8 health male rats receiving same volume solvent served as normal control. The body weight

taken food amount

fasting blood glucose

plasma insulin content and the morphology of the spleen were measured and examined  to validate the animal models.     Results   Blood glucose

total plasma lipids and cholesterol of model rats were markedly increased after STZ injection. And there were some other symptoms of model rats

such as polyuria

polydipsia and polyphagia

which indicated that diabetes had been induced in the models. The male model rats had higher mortality

body weight

triglyceride level and lower plasma insulin than in female (

P

<

0.05). Hypertrophy and hyperplasia of the islets of Langerhans in the male pancreas were more characteristic than in that of the female. Rosiglitazone reduced fasting blood glucose in the female rats (

P

<

0.05)

but had no effect on it in the male rats.     Conclusion   Female Wistar rats are induced to develop type 2 diabetes mellitus after STZ injection and lardy diet. However

because STZ causes different damnification on the islets of Langerhans in the male and female rats

the male Wistar rats can not to be induced to have the disease by STZ and lardy diet.