title: Physiological characteristics of platelet/circulatory serotonin: study on a large human population.
abstract: The aim of this work was the study of platelet/circulatory serotonin (5-hydroxytryptamine, 5-HT), specifically alternative ways of its measurement and main physiological characteristics. The study was performed on a large human population (N=500) of blood donors of both sexes over the course of a longer time period (17 months). Owing to the heterogeneity in measurement of circulatory serotonin encountered in the literature, three ways of expression were comparatively studied: per unit number of platelets, per unit mass of platelet protein and per unit volume of whole blood. Results demonstrated unimodal distribution of individual frequencies of platelet/circulatory serotonin in the human population with the mean values of 579+/-169 ng 5-HT/10(9) platelets; 332+/-89.9 ng 5-HT/mg protein and 130+/-42.3 ng 5-HT/ml blood (mean+/-S.D.). A progressive decrease of serotonin level with age (18-65 years) was demonstrated, reaching statistical significance between the extreme age groups. No significant differences in the serotonin level between the sexes were observed. No seasonal oscillations in platelet/circulatory serotonin were found. Platelet serotonin demonstrated intra-individual stability over time. Finally, regarding the methodology of measurement, our results demonstrated a good correlation among the above-mentioned ways of expression of platelet/circulatory serotonin. This indicates the possibility of intercomparison of the literature reports expressing this physiological parameter either as 5-HT concentration in platelets or as 5-HT level in the circulation.
authors.affiliation: Ruder Boskovic Institute, Bijenicka 54, HR-10 000, Zagreb, Croatia. jernej@rudjer.irb.hr
authors.forename: B
authors.initials: B
authors.lastname: Jernej
authors.forename: M
authors.initials: M
authors.lastname: Banović
authors.forename: L
authors.initials: L
authors.lastname: Cicin-Sain
authors.forename: D
authors.initials: D
authors.lastname: Hranilović
authors.forename: M
authors.initials: M
authors.lastname: Balija
authors.forename: D
authors.initials: D
authors.lastname: Oresković
authors.forename: V
authors.initials: V
authors.lastname: Folnegović-Smalc
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D012016:Reference Values; D012701:Serotonin / Q000097:blood*; D012737:Sex Factors
chemical_list: D012701:Serotonin