Decreased levels of B-endorphin in circulating mononuclear leukocytes from patients with acute myocardial infarction

Lymphocytes can be activated to produce and release opioid peptides. We investigated the levels of immunoreactive β-endorphin in peripheral blood mononuclear cells from 11 patients with acute myocardial infarction. The concentrations of β-endorphin in mononuclear leukocytes of 30.2 ± 6.9 pg/ 10 6 cells on admission were in the normal range of 20-40 pg/10 6 cells and decreased significantly to 6.9 ± 1.9 pg/10 6 cells after 48 h (p < 0.05). Decreased levels of mononuclear leukocyte-associated β-endorphin in acute myocardial infarction may be due to the release of endogenous opioid after stimulation by stress and acute-phase reactants and play a role in inflammation and pain.