The effects of metformin and letrozole on endometrium and ovary in a rat model.

Objective: The effects of metformin and letrozole on endometrium and ovarian reserve were studied in a rat model.
Methods: Forty female Wistar albino mature rats at 8 weeks, weighing 180-260 g, were used for the study. These rats were randomly divided into four groups. Control group, eight rats, was given no medication by oral gavage. The rats in low-dose metformin group, 10 rats, were given 100 mg/kg/day of oral metformin. The rats in high-dose metformin group, 10 rats, were given 200 mg/kg/day of oral metformin. The rats in letrozole, 10 rats, were given 0.1 mg/kg/day of oral letrozole.
Results: There was statistically significant difference in the endometrial thickness between the treatment groups and control group. The primordial follicle count was comparable in all treatment groups compared with control. Finally, there was no significant difference in total follicle count between the treatment groups and control.
Conclusions: This study showed that both metformin and letrozole had similar effects on endometrium and ovary in the rat model. Additionally, metformin had a little effect on endometrium than letrozole. Although metformin and letrozole might have tendency to enhance the total follicle count in the rat model, they had comparable effects on ovarian follicles and did not change the ovarian reserve compared with control.