engleski

Physiological characteristics of platelet circulatory serotonin: study on a large human population

The aim of this work was the study of platelet/circulatory serotonin (5-HT), specifically alternative ways of its measurement and main physiological characteristics. Study was performed on a large human population (N=500) of blood donors of both sexes in the course of 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 579ą169 ng 5-HT/109 platelets ; 332ą89.9 ng 5-HT/mg protein, 130ą42.3 ng 5-HT/mL blood (mean+SD). 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 intraindividual 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.

platelet serotonin; age influence; seasonal oscillations; sex influence; intraindividual stability; 5-HT

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