Insulin-like growth factors and ovarian physiology.
OBJECTIVE
To review the available information regarding the roles of insulin-like growth factor (IGF)-IGF binding protein (IGFBP) system in ovarian physiology.


METHODS
Studies that specifically relate to the roles of ovarian folliculogenesis, oocyte maturation, and ovulation were identified through the literature and Medline searches.


RESULTS
Numerous actions of the IGFs have been demonstrated in the ovary, including an enhancement of cell proliferation, aromatase activity, and progesterone biosynthesis. The ovarian IGF system, comprised of IGF-I and IGF-II peptides, IGFBPs and IGF receptors, plays a significant role in the process of follicular development. In addition, IGF-I stimulates the meiotic maturation of follicle-enclosed oocytes in vitro via the IGF-I receptors. IGFBP-3 significantly inhibit gonadotropin-induced ovulation and oocyte maturation by neutralizing endogenously produced IGF-I. Thus, the intraovarian IGF-IGFBP system play a significant role in the processes of follicular development, oocyte maturation, and ovulation.


CONCLUSIONS
IGF-IGFBP systems have autocrine/paracrine regulatory actions in ovarian physiology. The disturbance of the IGF-IGFBP system in human ovaries may lead to an ovulation, disorders of androgen excess, and infertility.
Yoshimura
Y
Y
Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan.
D000818:Animals; D005260:Female; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D009865:Oocytes; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D013002:Somatomedins / Q000502:physiology*
D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I