BETA-ENDORPHIN RESPONSE TO EXERCISE - AN UPDATE

beta-Endorphin, a 31-amino-acid peptide, is primarily synthesised in t he anterior pituitary gland and cleaved from pro-opiomelanocortin, its larger precursor molecule. beta-Endorphin can be released into the ci rculation from the pituitary gland or can project into areas of the br ain through nerve fibres. Exercise of sufficient intensity and duratio n has been demonstrated to increase circulating beta-endorphin levels. Previous reviews have presented the background of opioids and exercis e and discussed the changes in beta-endorphin levels in response to ae robic and anaerobic exercise. The present review is to update the resp onse of beta-endorphin to exercise. This review suggests that exercise -induced beta-endorphin alterations are related to type of exercise an d special populations tested, and may differ in individuals with healt h problems. Additionally, some of the possible mechanisms which may in duce beta-endorphin changes in the circulation include analgesia, lact ate or base excess, and metabolic factors. Based on the type of exerci se, different mechanisms may be involved in the regulation of beta-end orphin release during exercise.