Insulin-like growth factor I receptors and IGF-I actions in neuronal cultures from the brain.
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.
Masters
B A
BA
Department of Physiology, College of Medicine, University of Florida, Gainesville 32610.
Raizada
M K
MK
D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008715:Methionine; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000502:physiology*
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D007457:Iodine Radioisotopes; D009419:Nerve Tissue Proteins; D007334:Insulin-Like Growth Factor I; D008715:Methionine; D017526:Receptor, IGF Type 1