title: Urinary 6-hydroxy-melatonin-sulfate excretion and circadian rhythm in patients with restless legs syndrome.
abstract: The precise etiology of the restless legs syndrome (RLS) is unknown. Sensory and motor symptoms of RLS worsen during evening/night, coincident with the physiological peak of pineal melatonin excretion. Decreased melatonin levels have been reported in insomnia, which is an associated feature of RLS. Melatonin substitution improved insomnia. A potential association between the idiopathic RLS (iRLS) and alterations in melatonin excretion was therefore explored. Daytime (7:00-22:00 hr) and night-time (22:00-7:00 hr) urinary excretion of 6-OH-melatonin-sulfate (aMLTs) was measured in 15 patients with iRLS and 11 controls by a radioimmunoassay. There was no significant difference between daytime and night-time urinary aMLTs excretion in iRLS as compared with controls (daytime: 6.14 +/- 5.20 ng versus 5.02 +/- 5.11 ng, NS; night-time: 21.07 +/- 17.05 ng versus 22.92 +/- 16.52 ng, NS). Our data do not provide evidence for a decrease of cumulative melatonin production in iRLS. Insomnia in RLS does not seem to be correlated with a deficit of melatonin.
authors.affiliation: Department of Neurology, University of Vienna, Vienna, Austria. gotthard.tribl@univie.ac.at
authors.forename: Gotthard G
authors.initials: GG
authors.lastname: Tribl
authors.forename: Franz
authors.initials: F
authors.lastname: Waldhauser
authors.forename: Thomas
authors.initials: T
authors.lastname: Sycha
authors.forename: Eduard
authors.initials: E
authors.lastname: Auff
authors.forename: Josef
authors.initials: J
authors.lastname: Zeitlhofer
mesh_terms: D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives* / Q000652:urine*; D008875:Middle Aged; D012148:Restless Legs Syndrome / Q000378:metabolism*
chemical_list: C054513:6-sulfatoxymelatonin; D008550:Melatonin