Urinary melatonin: a noninvasive method to follow human pineal function as studied in three experimental conditions
| Autor: | Tiina M. Mäkinen, Tiina Pääkkönen, Hannu Rintamäki, Juhani Hassi, Olli Vakkuri, Lawrence A. Palinkas, Juhani Leppäluoto |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male endocrine system medicine.medical_specialty Evening Light Urinary system Urine Biology Pineal Gland Melatonin Excretion Pineal gland Endocrinology Internal medicine medicine Humans Circadian rhythm Monitoring Physiologic Morning Temperature Circadian Rhythm medicine.anatomical_structure Area Under Curve Seasons hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Journal of Pineal Research. 40:110-115 |
| ISSN: | 1600-079X 0742-3098 |
| DOI: | 10.1111/j.1600-079x.2005.00300.x |
| Popis: | The aim of this study was to examine whether urinary melatonin, rather than urinary 6-sulfatoxymelatonin (aMT6s), can be used as an indicator of diurnally and seasonally changing melatonin secretion. The subjects (n=15) spent three separate 24-hr periods in a climatic chamber during winter (n=7) and summer (n=8). Blood and urine samples were obtained during each period at 2- to 5-hr intervals. Serum melatonin and urinary melatonin and aMT6s were assayed by radioimmunoassay. The serum melatonin levels increased nearly 10-fold from low daytime to high nocturnal values. The mean nocturnal increase of urinary melatonin was 1.7-fold and that of urinary aMT6s was 4.6-fold. Both urinary melatonin and aMT6s correlated significantly with area under the curve melatonin in serum during the night, during the day and throughout the entire 24-hr observation period in all cases. The ratio between urinary melatonin and aMT6s excretion showed significant diurnal variation, being ninefold higher at 16:00 hr than at 07:00 or at 09:00 hr. The ninefold decrease in the urinary melatonin/aMT6s excretion ratio between the evening and the morning may reflect increased liver metabolism of melatonin during the night. Both urinary melatonin and aMT6s are good indicators of melatonin secretion, but the variation is significantly smaller for the former molecule. |
| Databáze: | OpenAIRE |
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