AGE-RELATED-CHANGES IN MITOGEN-INDUCED BETA-ENDORPHIN RELEASE FROM HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

beta-Endorphin is an opioid peptide synthesized in the pituitary, hypo thalamus, and immunocytes, known to affect immune responses both when added in vitro and when its synthesis is increased in vivo (e.g., duri ng stress). We show here that, similar to its concentrations in periph eral blood mononuclear cells, the release of the opioid peptide from t hese cells after stimulation with polyclonal mitogens such as PHA or C on-A is also age dependent. Moreover, the effect of both mitogens on C a2+ homeostasis changes with age. Finally, the ionophore ionomycin and the Ca2+ ATPase blocker thapsigargin induce the same age related effe ct on beta-endorphin release. For these reasons, we suggest that calci um homeostasis might be important for the differences observed in the release of the opioid from cells obtained from younger (less than or e qual to 30 years) or older (greater than or equal to 45 years) volunte ers.