Encyclopedia of Cancer

Living Edition
| Editors: Manfred Schwab

Melatonin

  • David E. Blask
  • Richard G. Stevens
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27841-9_3617-3

Definition

Melatonin is an indoleamine synthesized from tryptophan and secreted from the pineal gland during the night. Peak concentrations in blood reach 60–80 pg/mL at around 2–3 a.m. in humans, whereas daytime levels are barely detectable. The half-life of melatonin in the blood is ∼ 50–60 min. As a result of first-pass metabolism in the liver, 90 % of melatonin is catabolized to 6-sulfatoxymelatonin, which is excreted in the urine. Most of the melatonin (e.g., 70 %) circulating in the bloodstream is bound to albumin. The absolute oral bioavailability of melatonin (2–4 mg) is 15 % with peak levels (2–4 ng/mL) being reached within ∼ 1 h of ingestion. The bioavailability of lower amounts (i.e., micrograms) of oral melatonin varies widely. Melatonin is regularly consumed from commercially available nutritional supplements by millions of people throughout the world primarily for sleep problems and/or jet lag. The long-term health implications of this are unknown.

Characteristics

Melatoni...

Keywords

Pineal Gland Melatonin Production Nocturnal Melatonin Human Breast Cancer Xenograft Linoleic Acid Uptake 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. Blask DE, Dauchy RT, Sauer LA (2005a) Putting cancer to sleep at night – the neuroendocrine/circadian melatonin signal. Endocrine 27:179–188CrossRefPubMedGoogle Scholar
  2. Blask DE, Brainard GC, Dauchy RT et al (2005b) Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats. Cancer Res 65:11174–11184CrossRefPubMedGoogle Scholar
  3. Lissoni P (2002) Is there a role for melatonin in supportive care? Support Care Cancer 10:110–116CrossRefPubMedGoogle Scholar
  4. Reiter RJ (2003) Melatonin: clinical relevance. Best Pract Res Clin Endocrinol Metab 17:273–285CrossRefPubMedGoogle Scholar
  5. Stevens RG (2005) Circadian disruption and breast cancer: from melatonin to clock genes. Epidemiology 16:254–258CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Laboratory of Chrono-Neuroendocrine Oncology, Department of Structural and Cellular BiologyTulane University School of MedicineNew OrleansUSA
  2. 2.University of Connecticut Health CenterFarmingtonUSA