Central serotonergic hypofunction in autism: results of the 5-hydroxy-tryptophan challenge test.
Some studies have suggested that disorders in the central serotonergic function may play a role in the pathophysiology of autistic disorder. In order to assess the central serotonergic turnover in autism, this study examines the cortisol and prolactin responses to administration of L-5-hydroxy-tryptophan (5-HTP), the direct precursor of 5-HT in 18 male, post-pubertal, Caucasian autistic patients (age 13-19 y.; I.Q.>55) and 22 matched healthy volunteers. Serum cortisol and prolactin were determined 45 and 30 minutes before administration of 5-HTP (4 mg/kg in non enteric-coated tablets) or an identical placebo in a single blind order and, thereafter, every 30 minutes over a 3-hour period. The 5-HTP-induced increases in serum cortisol were significantly lower in autistic patients than in controls, whereas there were no significant differences in 5-HTP-induced prolactin responses between both study groups. In baseline conditions, no significant differences were found in serum cortisol and prolactin between autistic and normal children. The results suggest that autism is accompanied by a central serotonergic hypoactivity and that the latter could play a role in the pathophysiology of autism.
Croonenberghs
Jan
J
The University Center of Child and Adolescent Psychiatry, A.Z. Middelheim, University of Antwerp, Antwerp, Belgium.
Wauters
Annick
A
Deboutte
Dirk
D
Verkerk
Robert
R
Scharpe
Simon
S
Maes
Michael
M
D006916:5-Hydroxytryptophan / Q000008:administration & dosage / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D018687:Antidepressive Agents, Second-Generation / Q000008:administration & dosage / Q000494:pharmacology*; D001321:Autistic Disorder / Q000097:blood / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D011388:Prolactin / Q000097:blood*; D012701:Serotonin / Q000502:physiology*; D012720:Severity of Illness Index
D018687:Antidepressive Agents, Second-Generation; D012701:Serotonin; D011388:Prolactin; D006916:5-Hydroxytryptophan; D006854:Hydrocortisone