INSULIN-LIKE GROWTH FACTOR-II IN FOLLICULAR-FLUID OF THE PATIENTS WITH INVITRO FERTILIZATION AND EMBRYO TRANSFER

Objective: To investigate whether insulin-like growth factor II (IGF-II) is present in follicular fluids (FF) and whether IGF-II in FF plays an important role on human ovarian function. Design, Setting, Patients: Insulin-like growth factor II concentrations were measured using an RIA technique in 46 samples of human FF obtained from 20 patients who were undergoing IVF and ET. The distribution profiles of unsaturated IGF-II binding protein were also investigated. Moreover, the effect of IGF-II on steroidogenesis by cultured granulosa cells (GCs) obtained simultaneously in the IVF-ET program was investigated. Results: The IGF-II levels in FF (92.7 +/- 7.5 nmol/L) were approximately eight times greater than those of IGF-I (11.4 +/- 1.0 nmol/L), and significant positive correlations were observed between these IGFs in FF. By Sephadex G-150 gel-chromatography of FF, two apparent peaks of unsaturated IGF-II binding protein could be detected in the high molecular weight (MW) (150 kd) and low MW (approximately 36 to 38 kd) regions. Additionally, IGF-II dose dependently increased the release of P and E2 from the cultured human GCs. Conclusions: These findings suggest that the large quantity of IGF-II in FF may play possibly some roles in the ovarian steroidogenesis.