Summary
To determine the effect of hypercortisolaemia on the melatonin circadian secretion
12 patients with pituitary or adrenal dependent Cushing's syndrome and 5 healthy controls
were studied. The melatonin circadian rhythm of secretion, observed in the control
group, was abolished in the patients with hypercortisolaemia. Mean nocturnal melatonin
levels and the integrated 24-hour secretion were significantly lower in the patients
studied than those of the controls. Thus, in patients with Cushing's syndrome the
melatonin levels are decreased and the circadian rhythm of this hormone is abolished.
Key-Words
Melatonin - Circadian Rhythm - Healthy Subjects - Hypercortisolaemia
