Ovary and ovulation: Insulin-like growth factor binding protein-3 (IGFBP-3) serum concentrations and ovarian responsiveness in in-vitro fertilization

The growth hormone (GH)/insulin-like growth factor-I(1GF-I) axis seems to play an important role in ovarianresponsiveness. Recently IGF binding protein-3 (IGFBP-3)serum concentrations have been reported to be a goodmarker of GH/IGF-I axis activity. In view of this finding,we measured IGFBP-3 serum concentrations in 29 womenundergoing in-vitro fertilization. We found a significantcorrelation among IGFBP-3 serum concentrations andmarkers of ovarian stimulation including efficacy index,serum oestradiol concentrations and the number of follicleson the day of human chorionic gonadotrophin (HCG)administration. The results of our study add additionalevidence to the importance of the GH7IGF-I system inregulating ovarian responsiveness to gonadotrophin stimu-lation.Key words: IGFBP-3/TVF/ovanan responsivenessIntroductionThe outcome of in-vitro fertilization (IVF) and ovulationinduction is strongly dependent on ovarian responsiveness toexogenous stimulation. The growth hormone (GH)/insulin-likegrowth factor-I (IGF-I) axis seems to play an important rolein ovarian responsiveness. The other major variables are age,follicle stimulating hormone (FSH) and luteinizing hormone(LH) (Ebrahim et al, 1993; Shoham et al, 1993; Seibel et al,1995). The evidence for the importance of the GH/IGF-I axisfor ovarian responsiveness to gonadotrophin stimulation comesfrom clinical studies where GH or growth hormone-releasinghormone (GHRH) treatments have been successfully used toimprove the ovarian response to gonadotrophins, and to facilit-ate follicular growth (Homburg et al, 1988; Hughes et al,1991; Ibrahim et al, 1991). In addition, decreased GH secretorycapacity in women with ovulatory dysfunction and an inversecorrelation between the amount of GH released after clonidinechallenge and the amount of human menopausal gonadotrophin(HMG) used for ovulation induction have been described(Menashe etal, 1990; Ovesen et al, 1992). Furthermore, IGF-1influences many aspects of ovarian function (Giudice, 1992).IGF-I serum concentrations are claimed to be a better2208marker of long-term GH/IGF-I axis activity than GH serumconcentrations (Barkan et al, 1988). Recently IGF bindingprotein-3 (IGFBP-3) serum concentrations have been reportedto be an even better marker of GH/IGF-I axis activity inhypersecretory states (Grinspoon et al, 1995) and hyposecre-tory states (Hasegawa et al, 1993), as well as in a healthypopulation (Blum et al, 1993).In view of these findings, we carried out a study to determinethe relative contribution of IGFBP-3 serum levels in predictingovarian responsiveness to exogenous gonadotrophin stimula-tion. We compared it with the contributions of age and basalLH, FSH and GH concentrations.Patients and methods