title: Insulin-like growth factor-I (IGF-I) colocalizes with IGF-binding proteins (IGFBPs) in mouse and rat ovary.
abstract: The cellular localization of insulin-like growth factor (IGF)-I mRNA, IGF-I peptide, and IGF-binding proteins (IGFBPs) was examined in mouse and rat ovaries through use ofin situ hybridization and immunohistochemical methods. IGF-I mRNA was found to be most abundant in granulosa cells, although lower levels were also detected in cells of the theca interna, stroma, and corpus luteum. In contrast, IGF-I immunoreactivity was undetectable or low in granulosa cells, weak and variable in oocytes, high in theca interna and the corpus luteum, and highest in the stroma. Antibodies directed against IGFBP-2, 3, and 5 yielded similar patterns of immunoreactivity to that observed for IGF-I peptide. The results indicate that IGF-I is synthesized in ovarian follicles, and that IGF-I of ovarian or systemic origin becomes localized to sites containing IGFBPs in the ovary.
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., T2N 4N1, Calgary, Alberta, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Goubau
authors.forename: B D
authors.initials: BD
authors.lastname: Murphy
authors.forename: V K
authors.initials: VK
authors.lastname: Han
authors.forename: G A
authors.initials: GA
authors.lastname: Schultz