Beta-endorphin, ACTH and cortisol secretion were measured in twelve healthy adult males after nasal spray administration 200 IU salmon calcitonin. A significant increase in plasma beta-endorphin, from 19.2 ng/l under basal conditions to a peak of 27.1 ng/l at 30 min was recorded. Plasma ACTH and cortisol were not affected. In individual subjects the beta-endorphin level was increased in eight of the twelve, ACTH rose in three and cortisol did not change in any of them. The data indicate that calcitonin induced a beta-endorphin increase independent of enhanced corticotrophin-cortisol release.