Effect of beta-endorphin on cell growth and cell death in human peripheral blood lymphocytes

Beta-endorphin (beta-end) was investigated for its ability to influence sequential metabolic events that accompany the movements of T-lymphocytes into the cell cycle. When cultured lymphocytes are exposed to this endogenous opioid peptide an increase in polyamine transport across cell membrane is observed. This membrane modification is an early cell cycle event, whose enhancement leads to the intracellular polyamine accumulation. It is shown that beta-end is able to enhance spermidine transport and that the exposition of cells to this peptide is perceived as an apoptotic signal. The possible relationship between induction of apoptotic death and enhancement of polyamine uptake is discussed.