INSULIN-LIKE-GROWTH-FACTOR (IGF)-I AND IGF BINDING PROTEIN-3 CONCENTRATIONS IN FLUID FROM HUMAN STIMULATED FOLLICLES

Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 (IGFBP- 3) play an important role in regulating follicle growth and maturation . We have evaluated whether responsiveness to gonadotrophins during an in-vitro fertilization (IVF) treatment is related to follicular fluid IGF-I and IGFBP-3 concentrations. We also investigated if a differenc e is present in IGF-I and IGFBP-3 concentrations between patients trea ted with human menopausal gonadotrophin (HMG) and patients treated wit h highly purified follicle stimulating hormone (FSH). We have measured IGF-I and IGFBP-3 in follicular fluid from pre-ovulatory follicles in an IVF programme. All 70 patients were stimulated after being down-re gulated with a gonadotrophin-releasing hormone (GnRH) analogue. IGF-I concentrations in follicular fluid were significantly inversely correl ated with the number of ampoules FSH administered and number of days o f FSH administration, and significantly correlated with the number of follicles aspirated. IGFBP-3 concentrations were not correlated with a ny other parameter measured nor were IGF-I and IGFBP-3 concentrations correlated. IGFBP-3 concentrations were significantly higher in patien ts receiving highly purified FSH compared with patients receiving HMG (P < 0.005). These results are new evidence that IGF-I concentration i n follicular fluid is higher in women who respond better to follicular stimulation, i.e. women who grow many follicles, women who need a sho rter duration of stimulation and women who need fewer ampoules FSH bef ore oocyte retrieval.