Objective: To investigate the possibility of insulin-like growth factor-I (IGF-I) as an adjunctive factor for ovulation induction.
Methods: The model of anovulatory mice was established by single injection of testosterone propionate. Thirty anovulatory mice were divided into 3 groups, each contained 10 mice. IGF-I 1 microgram + human menopausal gonadotropin (hMG) 5 IU, IGF-I 2 micrograms or hMG 10 IU alone was injected intraperitoneally to each group respectively. Cyclic changes of vaginal smear and numbers of oocytes in fallopian tubes were used to assess the effect.
Results: Vaginal smears of 8 mice in IGF-I + hMG group, 6 mice in hMG group and 2 mice in IGF-I group returned to normal cyclic pattern. The differences between IGF-I + hMG group and IGF-I or hMG groups were significant (P < 0.01 and P < 0.05), but the difference between IGF-I group and hMG group was not significant (P > 0.05). The average numbers of oocytes within fallopian tubes were 12.3 in IGF-I + hMG group and 9.2 in hMG group (P < 0.05). In IGF-I group there were no oocytes in the fallopian tubes of two mice whose vaginal smears returned to normal.
Conclusion: IGF-I may be a potential agonist agent for ovulation induction.