BETA-ENDORPHIN ENHANCES POLYAMINE TRANSPORT IN HUMAN-LYMPHOCYTES

Opioid peptides, such as beta-endorphin (beta-end), are capable of mod ulating in vitro proliferative response of lymphocytes. We attempted t o determine the role of extracellular polyamines in the regulation of immune responses to opioid peptides by measuring the extent of polyami ne uptake as adaptional response to cell activation. beta-end dose-dep endently enhanced the incorporation of radioactive spermidine and sper mine. When the cells were depleted of spermidine, with addition of spe cific inhibitors of both biosynthesis and interconversion pathway, a l arge increase in the incorporation of radioactive spermidine was obser ved. This effect appeares to be specific for beta-end, although a non- opiate-specific receptor could be involved, since beta-end-enhanced in corporation of radioactive spermidine is not blocked by naloxone. We c onclude that the enhancement of polyamine incorporation may be conside red as an integral component of lymphocyte activation by beta-end.