Plasma-free homovanillic acid: Within- and across-day stability in children and adults with tourette's syndrome

Mark A. Riddle, James F. Leckman, George M. Anderson, Sharon I. Ort, Maureen T. Hardin, John Stevenson, Donald J. Cohen

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Within- and across-day stability of plasma-free homovanillic acid (pHVA) was assessed in children and adults with Tourette's syndrome. A diurnal fall in pHVA was observed in 13 of 15 subjects. There was a small but significant (p < .0001) decrease (8%) in mean morning pHVA levels obtained just 20 minutes apart (8:30 A.M. and 8:50 A.M.). A substantial and significant (p < .001) mean decrease in pHVA (25%) was observed when samples obtained between 8:00 and 8:30 A.M. were compared with samples obtained at 12:00 noon. Changes in pHVA levels observed during the afternoon (between 12:00 noon and 4:00 P.M.) were small, nondirectional, and nonsignificant. Repeated measurement of morning pHVA in the same individual after 24 or more hours revealed marked increases or decreases in many individuals, suggesting that morning pHVA is not a stable measure. The results of this and previous studies suggest that pHVA obtained at 12:00 noon or later in the day may be a more reliable measure of centrally produced HVA. Further studies are needed regarding the stability of pHVA over time.

Original languageEnglish (US)
Pages (from-to)2145-2151
Number of pages7
JournalLife Sciences
Volume40
Issue number22
DOIs
StatePublished - Jun 1 1987
Externally publishedYes

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • Pharmacology, Toxicology and Pharmaceutics(all)

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