title: Circadian rhythm of plasma tryptophan in clinically healthy subjects and patients with endogenous depression.
abstract: Variations of plasma tryptophan along the 24-h scale are studied in clinically healthy subjects and in patients with endogenous depression. In both groups a circadian rhythm in free and total tryptophan has been found. In healthy subjects plasma tryptophan levels were higher during the night in comparison with daytime hours; the opposite was demonstrated in depressed patients. The possible physiopathological mechanisms underlying the different behavior of plasma tryptophan in the 24-h span, in these two groups of subjects, are discussed.
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D003866:Depressive Disorder / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D014364:Tryptophan / Q000097:blood*
chemical_list: D014364:Tryptophan