Key result
IGF-I specifically binds to high-affinity receptors on neurites and induces synthesis of specific proteins in the 48,000-50,000 Mr range in primary neuronal cultures.
IGF-I receptors on neuronal cultures mediate the induction of specific proteins, suggesting a role in neurotrophic activity in the brain.
Indicates IGF-I neurotrophic potential via neuronal receptors; leaves open in vivo translation or clinical relevance.
Neurons in primary culture have been used to study IGF-I receptors and IGF-I-induced cellular actions in the brain. Intact neurons in culture specifically bind [125I]IGF with high affinity. The potency for the competition of [125I]IGF-I binding was IGF-I > IGF-II > insulin. A curvilinear Scatchard plot represented high-affinity (0.15 nM) and low-affinity (3 nM) binding sites with a Bmax of 142 fmol and 618 fmol/mg protein, respectively. These binding sites are predominantly localized on neurites with relatively few sites on the cell soma. IGF-I induced synthesis of protein(s) in the M(r) range of 48,000-50,000 with pI values of 6.1-6.4. These observations show that IGF-I receptor mediates induction of specific proteins and suggest that these proteins may be involved in the neurotrophic activity of IGF-I in the brain.
No takes yet. Share an insight, caveat, or question.
Masters et al. (1993) studied this question. IGF-I vs. IGF-II and insulin was evaluated on Binding affinity and protein synthesis. IGF-I specifically binds to high-affinity receptors on neurites and induces synthesis of specific proteins in the 48,000-50,000 Mr range in primary neuronal cultures.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: