title: beta-Endorphin enhances lymphocyte proliferative responses.
abstract: The opioid peptides alpha- and beta-endorphin and [D-Ala2, Met5]enkephalin were investigated for their effect on the proliferation of resting and activated rat splenic lymphocytes in vitro. beta-Endorphin enhanced the proliferative response of spleen cells to the T cell mitogens concanavalin A and phytohemagglutinin. The effect of beta-endorphin was dose dependent and occurred at peptide concentrations similar to those found in rat plasma. alpha-Endorphin and [D-Ala2, Met5]enkephalin did not affect the proliferative responses to any mitogen tested. Furthermore, the potentiating effect of beta-endorphin was not reversed by treatment with 10 microM naloxone. None of the peptides had any effect on resting, unstimulated spleen cells or on the response to a mixture of lipopolysaccharide and dextran sulfate, which is specifically mitogenic for B lymphocytes. The pharmacological properties of the beta-endorphin potentiation indicate that the effect may be mediated by a nonopiate but beta-endorphin-specific mechanism. These results suggest a possible role for peripheral beta-endorphin and may provide a link between stress and disease susceptibility.
mesh_terms: D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D003208:Concanavalin A; D004261:DNA Replication / Q000187:drug effects; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives*; D004745:Enkephalins / Q000494:pharmacology; D005260:Female; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D001615:beta-Endorphin
chemical_list: D000700:Analgesics; D004723:Endorphins; D004745:Enkephalins; D003208:Concanavalin A; D009270:Naloxone; D004744:Enkephalin, Methionine; D001615:beta-Endorphin; C013801:enkephalin-Met, Ala(2)-