title: Impaired nocturnal synthesis of melatonin in patients with cardiac syndrome X.
abstract: We investigated nocturnal secretion pattern of melatonin in patients with cardiac syndrome X and healthy subjects. The present study performed in five patients with cardiac syndrome X and in nine healthy controls. Blood samples from all subjects were collected every 2 h intervals between 22:00 and 08:00 h. Melatonin levels were measured with a radioimmunoassay kit. Patients with cardiac syndrome X secreted less nocturnal melatonin at 02:00 h than control subjects (P=0.04). Peak and Delta melatonin (peak-lowest melatonin) were found lower in patients with cardiac syndrome X (P=0.039 and P=0.028, respectively). In conclusion patients with cardiac syndrome X show a markedly decreased nocturnal melatonin synthesis. Our study provides useful information about melatonin synthesis and release in patients with cardiac syndrome X might help physicians in managing these patients.
authors.affiliation: Department of Cardiology, Medical School, Trakya University, Edirne, Turkey. altun@medscape.com
authors.forename: Armagan
authors.initials: A
authors.lastname: Altun
authors.forename: Mevlut
authors.initials: M
authors.lastname: Yaprak
authors.forename: Meryem
authors.initials: M
authors.lastname: Aktoz
authors.forename: Arzu
authors.initials: A
authors.lastname: Vardar
authors.forename: Ugur Altun
authors.initials: UA
authors.lastname: Betul
authors.forename: Gultac
authors.initials: G
authors.lastname: Ozbay
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000096:biosynthesis* / Q000097:blood; D017566:Microvascular Angina / Q000378:metabolism*; D008875:Middle Aged; D010870:Pineal Gland / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D008550:Melatonin