title: Circadian variation in 5-hydroxytryptamine levels in human blood.
abstract: This study investigates, on a circadian basis, the variation in blood serotonin for a group of 64 healthy persons (volunteers of a Bundeswehr-Ausbildungskompanie); a pronounced circadian rhythm of 5-HT has been found. The variation in daily absolute levels is influenced by novelty stress; by this we refer to the stress resulting from initial contact between the person sampling blood and the patient. Obviously this diminishes as blood is repeatedly withdrawn from the same individual. Exposure to this situation results in an overall decrease in serotonin levels and a modification of the circadian pattern.
mesh_terms: D002940:Circadian Rhythm; D002986:Clinical Trials as Topic; D006801:Humans; D008297:Male; D012701:Serotonin / Q000097:blood*; D013312:Stress, Physiological
chemical_list: D012701:Serotonin