Growth hormone response to L-Dopa and clonidine in autistic children

George M Realmuto, Jonathan B Jensen, Elizabeth Reeve, Barry D. Garfinkel

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Studies have shown abnormal pituitary hormone responses to neuroendocrine agonists in autistic subjects. Two probes (clonidine and L-Dopa) were used to investigate neuroendocrine responses through changes in growth hormone levels. Seven medication-free autistic subjects (ages 6.6 to 19.1) were evaluated and compared to 14 normal controls. Growth hormone was collected at 30-min intervals during the entire study. Clonidine was administered first (dose: 0.15 mgm2), and samples were collected for 180 min. L-Dopa was then administered (dose: 250 mg for subjects <70 lb and 500 mg for subjects >70 lb), and samples were collected for 120 min. There was no difference in the amplitude of the clonidine or L-Dopa peak growth hormone responses in the control versus the autistic subjects. In the autistic subjects, the L-Dopa-stimulated growth hormone peak was delayed and the clonidine growth hormone peak was premature. A statistical difference with the control subjects was found when consideration was given to both the premature response of growth hormone to clonidine and the delayed response to L-Dopa (p=.01, Fisher's Exact Test). These findings suggest possible abnormalities of both dopaminergic and noradrenergic neurotransmission in subjects with autism.

Original languageEnglish (US)
Pages (from-to)455-465
Number of pages11
JournalJournal of Autism and Developmental Disorders
Issue number4
StatePublished - Dec 1 1990


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