Circadian variations of norepinephrine and melatonin in extremely obese men and women

The relationship between 24-h variations of norepinephrine (NE), melatonin (MEL) and the values of body mass index (BMI) and waist-to-hip circumference ratio (WHR) was evaluated. The circadian rhythm of NE and MEL was examined in 26 extremely obese patients (14 men and 12 women) and 24 healthy volunteers (13 men and 11 women) with normal body weight. In extremely obese men and women it showed following similar characteristics. In 9/14 obese men (64.3 %) and 8/12 obese women (66.7 %) mean 24 h NE levels were significantly higher than those in controls, while only moderate elevation of mean 24 h NE values was found in the remaining patients. Mean 24 h MEL concentrations were markedly higher in all obese patients studied. Moreover, the disturbances of MEL secretion in the form of acrophase shift and the suppression of its 24-h rhythmicity were observed in-patients with markedly higher NE levels. Mean 24-h NE concentrations correlated positively with mesor values of MEL and also with body mass and fat distribution as measured by BMI and WHR, respectively. In contrast, no significant correlation was found between the values of BMI index, WHR ratio and MEL.