Biogenic amines in anorexia nervosa: circadian rhythm in urinary excretion and influence of posture and physical task load on plasma catecholamines.

To investigate the sympathetic response in anorexia nervosa (AN) patients to stimuli occurring in normal life, biogenic amines were studied in 10 female outpatients. As control groups 10 lean and 10 normal weight healthy female subjects were included. It was hypothesized that the lean control group would have intermediate values between the AN patients and the normal weight controls. The AN patients and the lean controls had a mean underweight of 33.1% and 13.7%, respectively. For the excretion in 24-hr urine, differences among the groups were observed for several compounds, unexpectedly the values being lowest for the patients and highest for the lean controls. Furthermore, the lean controls had a higher excretion of a number of compounds in diurnal than in nocturnal urine, whereas this effect was absent or reversed for the AN patients and intermediate for the normal weight controls. Plasma norepinephrine was highest in the patients and lowest in the lean controls. The catecholamine response to postural changes and physical exercise did not differ among the groups. The results obtained indicate neither a (linear) relationship between underweight and the metabolism of biogenic amines nor a disturbed response to sympathetic stimulation in AN, but suggest an altered metabolism of biogenic amines in patients suffering from AN.