Binding of [125I]-Insulin-Like Growth Factor-1 (IGF-1) in Brains of Alzheimer’s and Alcoholic Patients
Patients with chronic alcoholism and/or Alzheimer’s disease suffer from degenerative changes in the cerebral cortex and hippocampus. To investigate possible changes in IGF-1 receptor binding sites in brain tissue of patients with these pathological conditions, the binding of [125I]-IGF-1 was determined in tissues obtained from control, Alzheimer’s and/or patients with a history of alcoholism. The four experimental groups examined consisted of patients from similar age groups. Specific binding of [125I]-IGF-1 to cerebral cortical membranes from Alzheimer’s patients had significantly more binding sites than age-matched controls, alcoholic patients and alcoholic patients with Alzheimer’s disease. Regression analyses indicated that there were no significant differences in [125I]-IGF-1 binding in cerebral cortex with regard to age of patients (1.1% of total variance with a range of 52 to 92 years). Likewise, the time interval between death and autopsy contributed only 1.4% to the total variance in IGF-1 binding. No statistical differences in [125I]-IGF-1 binding were noted in hippocampal tissue from the various patient groups. Thus, human IGF-1 binding sites in cerebral cortex and hippocampus appear to be relatively stable for a number of variables. The increase in cerebral cortical [125I]-IGF-1 binding sites could be due to upregulation of IGF-1 receptors resulting from a decrease in IGF-1 levels in Alzheimer’s patients.
KeywordsCerebral Cortex Alcoholic Patient Nerve Growth Factor Receptor Intrinsic Tyrosine Kinase Activity Hippocampal Membrane
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