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 growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) behavior in spontaneous and in superstimulated cycles.


METHODS
Estradiol, GH, IGF-I, and IGFBP-3 were evaluated in serum and in follicular fluid during spontaneous and stimulated cycles.


METHODS
Department of Obstetrics and Gynecology, University of Naples, Naples, Italy.


METHODS
Ninety-two patients with regular menstrual cycles and tubal and/or male factor infertility undergoing treatment with an IVF program.


METHODS
The superstimulated IVF program uses leuprolide acetate suppression followed by hMG in a sequential manner in the subsequent cycle. After sufficient follicular development, hCG was administered, followed 34-36 hours later by oocyte retrieval.


METHODS
Growth hormone, IGF-I, and IGFBP-3 were assayed by RIA and immunoradiometric assay techniques.


RESULTS
Growth hormone levels in serum and in follicular fluid were higher after FSH-stimulated cycles than after physiologic cycles. Serum and follicular fluid IGF-I did not change during physiologic and FSH-stimulated cycles. Serum IGFBP-3 decreased only in FSH-stimulated cycles. Levels of IGFBP-3 in follicular fluid were lower than serum levels in late follicular phase both in physiologic and in FSH-stimulated cycles.


CONCLUSIONS
Reduction of IGFBP-3 is an important mechanism allowing a larger local availability of free IGFs, which modulate the response of follicles to gonadotropin stimulation. This effect is amplified in stimulated cycles.
Amato
G
G
Department of Endocrinology, Second University of Naples, Italy.
Izzo
A
A
Tucker
A
A
Bellastella
A
A
D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D004958:Estradiol / Q000097:blood / Q000378:metabolism; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism*; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D016729:Leuprolide / Q000494:pharmacology; D008297:Male; D008596:Menotropins / Q000494:pharmacology; D008597:Menstrual Cycle / Q000187:drug effects / Q000378:metabolism*; D013268:Stimulation, Chemical
D018931:Antineoplastic Agents, Hormonal; D018972:Insulin-Like Growth Factor Binding Protein 3; D004958:Estradiol; D008596:Menotropins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D016729:Leuprolide