We evaluated the effects of insulin-like growth factor binding protein- 3 (IGFBP-3) on insulin-like growth factor I (IGF-I)-stimulated follicular growth, oocyte maturation ovarian steroidogenesis and angiotensin II (Ang II) production, and intrafollicular plasminogen activator (PA) activity using all in vitro perfused rabbit ovary preparation. Exposure to 102 ng/ml of IGF-I significantly stimulated follicular development, oocyte maturation, and the secretion rate of Ang II-like immunoreacivity (Ang II-IR) in perfused rabbit ovaries. The concomitant addition of IGFBP-3 (1 to 103 ng/ml) to the perfusate blocked the stimulatory effects of IGF-I in a dose-dependent manner. The percent increase in follicle diameter in IGF-I-treated ovaries with or without IGFBP-3 for 12 h was significantly correlated with the secretion tale of Ang II-IR at 12 h after exposure to IGF-I. The secretion rate of estradiol (E2), but not progesterone, was significantly increased in response to IGF-I administration, with IGFBP-3 reduced the IGF-I-induced secretion rate of E2 in a dose-dependent manner. A monoclonal antibody recognizing the type I receptor, αIR-3, also significantly blocked IGF-I- stimulated follicular growth, oocyte maturation, and Ang II-IR secretion. The addition of either 103 ng/ml of IGFBP-3 or 1 μg/ml of αIR-3 to the perfusate significantly inhibited the intrafollicular PA activity stimulated by IGF-I. In conclusion, these results indicate that IGF-I stimulates follicular growth, at least in part, by stimulating the ovarian production of Ang II. Thus, IGF-I and Ang II may interact in the mechanisms that control follicular development.
|ジャーナル||Japanese Journal of Fertility and Sterility|
|出版ステータス||Published - 1997 1 1|
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