CALCITONIN AND BETA-ENDORPHIN SECRETION

Calcitonin is a peptide hormone secreted by the C-cells of the thyroid gland. This hormone mainly acts in preventing bone resorption. Furthe rmore, calcitonin is involved in other biological actions, and in part icular it is able to relieve pain independently of its peripheral effe cts on bone. Here, we examine the possible mechanisms of calcitonin-in duced analgesia, with particular regard to the opioid system involveme nt. Several studies in animals and in humans demonstrate that calciton in increases plasma beta-endorphin levels, acting at the hypothalamic and/or at the pituitary level, either directly or indirectly, through monoaminergic neurotransmitters. However, this calcitonin-induced beta -endorphin release has not always been observed. These different resul ts are discussed, and a possible implication of sex and/or calcitonin dose employed has been examined. We conclude that the analgesic effect s of calcitonin are multifactorial, and beta-endorphin plays its own s pecific role.