Beta-endorphin concentrations in resting peripheral mononuclear cells and after treatment with PHA or serotoninergic drugs in human aging, Alzheimer's disease, and Down's syndrome

We measured the concentrations of beta-endorphin in resting peripheral blood mononuclear cells obtained from normal subjects of different ages and from age-matched patients with Down's syndrome or Alzheimer's disease. We also measured beta-endorphin concentrations in peripheral blood mononuclear cells obtained from subjects of different ages after treatment with PHA or serotoninergic drugs. The results show that in normal subjects the concentrations of the peptide increase after 30 years of age and remain constant up to 99 years. After stimulation with PHA, the release of beta-endorphin in cells from subjects older than 30 years increases, leading to a decrease in contents, whereas it is unchanged in younger subjects. In patients with Down's syndrome or Alzheimer's disease, beta-endorphin concentrations in peripheral blood mononuclear cells behave similarly to those in age-matched normal subjects. Treatment in vivo with the serotoninergic agonist chlorimipramine induces an increase in beta-endorphin concentrations in peripheral blood mononuclear cells that is significantly greater in subjects over 30 years old than in younger subjects.