Abstract: Objective · To investigate the effect of metformin on insulin resistance (IR)-related metabolic parameters in olanzapine-bearing rats.  Methods · Thirty female SD rats were randomly divided into metformin intervention group, olanzapine group and control group. During the first 6 weeks, 5 mg /(kg·d) olanzapine was given to the two test groups . The control group was given the same amount of saline. From the 7th week, the intervention group began to combine with metformin 500 mg / (kg·d), while the olanzapine group combined with the same amount of saline, continuing  for 4 weeks. At the end of 6th week and 10th week, intraperitoneal glucose tolerance and homeostasis model assessment IR index were assessed.  Results · The area under the glucose tolerance curve (P=0.040) and the IR index (P=0.000) were significantly higher for the intervention group and the olanzapine group than the control group at the end of 6th week. At the 10th weekend, the glucose tolerance (P=0.015) and IR index in the intervention group were significantly lower than those in the olanzapine group (P=0.001).  Conclusion · Metformin may rectify the impaired glucose tolerance and improve IR induced by olanzapine partly.

Key words: olanzapine, metformin, insulin resistance, glucose tolerance