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Follicular fluid insulin-like growth factor-I and insulin-like growth factor-binding protein-1 and -3 vary as a
L Stadtmauer1, A Vidali, S R Lindheim
1Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, Columbia Presbyterian Medical Center, New York, New York 10032, USA.
Purpose:
Follicular fluid concentrations of insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein (BP)-1, and IGFBP-3 in 57 women undergoing in vitro fertilization and embryo transfer were examined to determine whether levels reflected differences in patients' exposure to gonadotropin stimulation and a diminished ovarian reserve.
Methods:
Preovulatory follicular fluid was obtained from both gonadotropin-stimulated and unstimulated cycles. Subjects were grouped according to normal or decreased ovarian reserve and whether or not they received gonadotropin stimulation.
Results:
The mean follicular fluid concentrations of IGF-I and IGFBP-1 were significantly lower in the "decreased" ovarian reserve group compared with the "normal" ovarian reserve group, with no change in estradiol or IGF-II levels. This resulted in a decreased molar IGF-I: BP ratio and an increased molar IGF-II:IGFBP-1 ratio. In unstimulated cycles, mean follicular fluid concentrations of IGFs did not differ significantly compared with those in stimulated cycles, whereas concentrations of IGFBP-1 and IGFBP-3 were significantly lower, leading to higher molar ratios of the IGFs to the binding proteins.
Conclusions:
Follicular fluid IGF and binding proteins vary as a function of ovarian reserve and gonadotropin stimulation. This may reflect either differences in oocyte quality or a suboptimal follicular fluid environment.