[Changes in beta-endorphin and its messenger RNA in pituitary, hypothalamus, lymphocytes and blood plasma during cold...

Changes of beta-endorphin (beta-EP) and its mRNA in pituitary (P), hypothalamus (HT), lymphocytes (LC) and blood plasma (BP) during cold acclimation of SD male rats were studied by beta-EP mRNA dot blot, RP-HPLC and beta-EP radio-immunoassay (RIA). Experimental results showed: (1) After cold-exposure for 1 week pituitary beta-EP mRNA increased significantly with the appearance of stimulated cellular immune function. (2) beta-EP mRNA in hypothalamic immune center and peripheral LC increased when cold acclimation of animals was established for a cold exposure of 2 weeks (C2W). (3) From C2W onward, plasma beta-EP also continued to increase, indicating an augmented state of cellular immune function. As LC and plasma beta-EP product continued to show increase, pituitary beta-EP mRNA content recovered to control level from C2W onward possibly due to a feedback mechanism through LC-P-HT axis.