Plasma tryptophan during weight restoration in patients with anorexia nervosa.
BACKGROUND
Anorexia nervosa (AN) is a mental disorder characterized by low weight and concerns about body shape and weight. Disturbance in serotonin function has been described as central to the psychobiology of this disorder. Plasma tryptophan (TRP), the essential amino acid needed for serotonin production, is known to be low following acute caloric restriction but has not been measured during the course of refeeding.


METHODS
Plasma TRP and other large neutral amino acids (LNAA) levels were measured in 26 female patients with AN and 15 control subjects. Patient levels were measured at admission for inpatient treatment, after 1 week of treatment, and upon weight restoration to weight > or =90% ideal body weight (IBW). For 17 patients, an additional assessment was made when weight reached 80% IBW. Plasma levels were obtained on one occasion from healthy control subjects.


RESULTS
Plasma TRP and TRP/LNAA ratio increased significantly during refeeding process. Plasma TRP in patients was 46.88 nmol/mL (SD = 19.59) on admission and 55.54 nmol/L/mL (SD = 8.1) at normal weight, p < .05. The ratio of TRP to LNAA was .11 (SD = .03) on admission and .13 (SD = .02) at normal weight, p < .05. Plasma TRP is significantly lower in low-weight patients than in healthy control subjects (TRP = 53.73 [SD = 8.21]), but there was no significant difference between control subjects and normal-weight patients.


CONCLUSIONS
Plasma TRP normalizes during the course of refeeding, supporting the hypothesis that serotonin function is disturbed in patients with anorexia nervosa.
Attia
Evelyn
E
Department of Psychiatry, Columbia University/The New York State Psychiatric Institute, New York, NY 10032, USA. ea12@columbia.edu
Wolk
Sara
S
Cooper
Thomas
T
Glasofer
Deborah
D
Walsh
B Timothy
BT
D000328:Adult; D021542:Amino Acids, Neutral / Q000097:blood; D000856:Anorexia Nervosa / Q000097:blood* / Q000628:therapy; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D002853:Chromatography, Liquid / Q000379:methods; D004750:Enteral Nutrition / Q000379:methods; D005260:Female; D006801:Humans; D013997:Time Factors; D014364:Tryptophan / Q000097:blood*
D021542:Amino Acids, Neutral; D014364:Tryptophan