Excretion of urinary catecholamine metabolites in anorexia nervosa: effect of body composition and energy intake

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Abstract
Metabolites of norepinephrine and dopamine were measured in urine from 12 women of normal body weight and from six women undergoing treatment for anorexia nervosa. The women with anorexia nervosa had 48% less body fat (14 ± 1 versus 27 ± 1%, p < 0.001), 9% less fat-free mass (36 ± 1 versus 40 ± 1 kg, p = 0.05), and 26% higher energy intake (2217 ± 147 versus 1750 ± 43 kcal, p < 0.01) on collection days compared to the normal weight women. Twenty-four-hour excretions of norepinephrine metabolites, 3-methoxy-4-hydroxyphen-ylethylglycol, 3,4-dihydroxyphenylethylglycol, and vanilmandelic acid were reduced (p < 0.01) in anorexia nervosa by 44, 48, and 39%, respectively. Excretion of homovanillic acid, the dopamine metabolite, was the same for both groups. Urinary 3-methoxy-4-hydroxyphenylethylglycol content was best predicted by percentage body fat in the normals (r = 0.63, p < 0.05) and for both groups combined (r = 0.79, p < 0.001). Urinary vanilmandelic acid showed a strong relationship with fat-free mass in the normal group (r = 0.84, p < 0.001) and for both groups combined (r = 0.79, p < 0.001). In contrast, urinary 3-methoxy-4-hydroxyphenylethylglycol and vanilmandelic acid and energy intakes were only weekly associated in the normals, but unrelated in the anorexics, or when the data from both groups were combined. Thus the reduced excretion of norepinephrine metabolites in anorexia nervosa appears to be associated with reduced body mass and altered body composition, particularly body fat, rather than to energy intake per se.