Objective: To study the changes of erectile function in diabetic rats and whether the function of penile erection was improved by the treatments of insulin. Methods: Male Sprague-Dawley rats were injected intraperitoneally with streptozotozin (STZ) to make experimental models of diabetes mellitus(DM). Diabetic rats were treated with insulin for 8 weeks

then injected with apomorphine in all of the rats

and penile erections were observed in order to evaluate their erectile function. Results: The penile erectile rates and penile erectile times in the DM rats (D group) were decreased significantly (P<0.01) than the controls (C group). And the above indexes in the diabetic rats treated with insulin(DI group) were significantly higher than those in D group ( P<0.01)

but lower than those in C group(P<0.01). Negative correlation was seen between the function of penile erection and HbA1C. Conclusion: The erectile function was seriously impaired in rats with DM

and the function of penile erection in diabetic rats was improved by the treatment of insulin.