[Beta-endorphin involved in the regulation of humoral immune function of rats during acute hypoxia]

In order to investigate the role of beta-endorphin in the regulation of humoral immune function of rats during acute hypoxia, the effects of beta-endorphin on mitogen-induced spleen lymphocyte DNA synthesis and hemolysin formation as well as IgG production to chicken egg albumen were observed. It was found that after rats received icv injection of beta-endorphin (1 ng/rat), the T-lymphocyte DNA content, the hemolysin-forming capacity of SRBC-sensitized rats and the IgG level were reduced significantly compared with the control (icv normal saline). Similar suppressive effects on immune function could be found after rats were exposed to 7 km altitude in a hypobaric chamber for 48 h. Pretreatment with icv injection of naltrexone, the immunosuppressive effects of acute hypoxia were partially blocked. Icv administration of beta-endorphin produced an increase in splenic cathcholamines, similar to those of hypoxia treated group (7 km for 12 h). All the above findings suggest that beta-endorphin may modulate the immune response to hypoxia stress via opioid receptor and its inhibitory action may be mediated by activating sympathetic nervous system.