ABSTRACT
Interest among researchers concerning the functions of the pineal hormone melatonin and the role played by it in the regulation of body temperature (BT) is considerable. The focus is on the immediate noncircadian effects of bright light in the discussion of melatonin’s role in thermoregulation. In humans, initial reports suggested that light did not suppress nighttime melatonin synthesis, but subsequent reports using a higher light intensity clearly showed suppression. The circadian profiles of melatonin levels of patients suffering from anorexia nervosa and bulimia nervosa were recently compared with the profiles of healthy controls. The literature concerning the exogenous administration of melatonin in nonhumans is also generally compatible with the hypothesis that melatonin has “direct” effects on BT. Melatonin also affects more indirect measures of thermoregulation such as changes in body weight and pelage. Exogenous administration of melatonin can also affect the seasonal rhythm of pelage or fur.
