INSULIN-LIKE-GROWTH-FACTOR BINDING PROTEIN-3 REDUCTION IN FOLLICULAR-FLUID IN SPONTANEOUS AND STIMULATED CYCLES

Objective: To investigate serum and follicular fluid insulin-like grow th factor-I (IGF-I) and insulin-like growth factor binding protein-3 ( IGFBP-3) behavior in spontaneous and in superstimulated cycles. Design : Estradiol, GH, IGF-I, and IGFBP-3 were evaluated in serum and in fol licular fluid during spontaneous and stimulated cycles. Setting: Depar tment of Obstetrics and Gynecology, University of Naples, Naples, Ital y. Patient(s): Ninety-two patients with regular menstrual cycles and t ubal and/or male factor infertility undergoing treatment with an IVF p rogram. Intervention(s): The superstimulated IVF program uses leuproli de acetate suppression followed by hMG in a sequential manner in the s ubsequent cycle. After sufficient follicular development, hCG was admi nistered, followed 34-36 hours later by oocyte retrieval. Main Outcome Measure(s): Growth hormone, IGF-I, and IGFBP-3 were assayed by RIA an d immunoradiometric assay techniques. Result(s): Growth hormone levels in serum and in follicular fluid were higher after FSH-stimulated cyc les than after physiologic cycles. Serum and follicular fluid IGF-I di d not change during physiologic and FSH-stimulated cycles. Serum IGFBP -3 decreased only in FSH-stimulated cycles. Levers of IGFBP-3 in folli cular fluid were lower than serum levels in late follicular phase both in physiologic and in FSH-stimulated cycles. Conclusion(s): Reduction of IGFBP-3 is an important mechanism allowing a larger local availabi lity of free IGFs, which modulate the response of follicles to gonadot ropin stimulation. This effect is amplified in stimulated cycles. (Fer til Steril(R) 1998;70:141-4. (C) 1998 by American Society for Reproduc tive Medicine.).