Expression of the genes for insulin-like growth factors and their receptors in bone during skeletal growth

D. D. Bikle, J. Harris, B. P. Halloran, C. T. Roberts, D. Leroith, E. Morey-Holton

    Research output: Contribution to journalArticle

    31 Scopus citations

    Abstract

    Insulin-like growth factors (IGF) are important regulators of skeletal growth. To determine whether the capacity to produce and respond to these growth factors changes during skeletal development, we measured the protein and mRNA levels for IGF-I, IGF-II, and their receptors (IGF-IR and IGF-IIR, respectively) in the tibia and femur of rats before and up to 28 mo after birth. The mRNA levels remained high during fetal development but fell after birth, reaching a nadir by 3-6 wk. This fall was most pronounced for IGF-II and IGF-IIR mRNA and least pronounced for IGF-I mRNA. However, after 6 wk, both IGF-I and IGF-IR mRNA levels recovered toward the levels observed at birth. In the prenatal bones, the signals for the mRNAs of IGF-II and IGF- IIR were stronger than the signals for the mRNAs of IGF-I and IGF-IR, although the content of IGF-I was three- to fivefold greater than that of IGF-II. IGF-II levels fell postnatally, whereas the IGF-I content rose after birth such that the ratio IGF-I/IGF-II continued to increase with age. We conclude that, during development, rat bone changes its capacity to produce and respond to IGFs with a progressive trend toward the dominance of IGF-I.

    Original languageEnglish (US)
    Pages (from-to)E278-E286
    JournalAmerican Journal of Physiology - Endocrinology and Metabolism
    Volume267
    Issue number2 30-2
    DOIs
    StatePublished - 1994

    Keywords

    • age
    • development
    • fetus
    • postnatal
    • tibia

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism
    • Physiology
    • Physiology (medical)

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