Mass spectrometric quantification of urinary 6-sulfatoxymelatonin: age-dependent excretion and biological variation.
Clin Chem Lab Med
; 59(1): 187-195, 2020 07 16.
Article
in En
| MEDLINE
| ID: mdl-32673281
ABSTRACT
Objectives:
Regulators of circadian rhythm, including melatonin, influence fundamental biological processes. Measuring the melatonin metabolite 6-sulfatoxymelatonin in urine can estimate melatonin production. 6-sulfatoxymelatonin is mainly analyzed by immunoassays, but these methods are hampered by cross-reactivity and poor reproducibility when used to analyze small molecules. Therefore, we validated a high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify 6-sulfatoxymelatonin in urine. We evaluated age-dependent 24-h excretion of 6-sulfatoxymelatonin into urine and the biological variation of urinary excretion in healthy individuals.Methods:
The online solid phase extraction method combined with LC-MS/MS was validated according to international guidelines, and used to measure the excretion of 6-sulfatoxymelatonin into urine of 240 healthy individuals. Biological variation of 6-sulfatoxymelatonin excretion was examined in 10 healthy individuals.Results:
Urinary 6-sulfatoxymelatonin results were well within the validation criteria (interassay coefficient of variation <5.4%, quantification limit 0.2 nmol/L). There was an age-related decrease in 6-sulfatoxymelatonin excretion into 24-h urine [F(5, 234)=13.9; p<0.001]. Within-subject variation of 6-sulfatoxymelatonin was 39.2% in day urine, 15.1% in night urine, and 12.2% in 24-h urine. Between-subject variation was 39.1% in day urine, 37.9% in night urine, and 36.8% in 24-h urine.Conclusions:
This MS-based method enables straightforward, reproducible, and sensitive quantification of 6-sulfatoxymelatonin in urine. Urinary 6-sulfatoxymelatonin levels decreased with age. Biological variation of 6-sulfatoxymelatonin excretion into urine was high between subjects and lower within subjects, indicating that repeated measurements of 6-sulfatoxymelatonin in 24-h urine are needed in future studies.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chromatography, Liquid
/
Tandem Mass Spectrometry
/
Melatonin
Limits:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Clin Chem Lab Med
Journal subject:
QUIMICA CLINICA
/
TECNICAS E PROCEDIMENTOS DE LABORATORIO
Year:
2020
Document type:
Article
Affiliation country:
Países Bajos