Document Detail

Alterations of the circadian melatonin rhythm by the electromagnetic spectrum: a study in environmental toxicology.
MedLine Citation:
PMID:  1509117     Owner:  NLM     Status:  MEDLINE    
The nightly production and secretion of melatonin by the pineal gland, an endocrine organ near the anatomical center of the brain, provides important time-of-day and time-of-year information to the remainder of the body. In mammals, the circadian rhythm of melatonin (low levels during the day and high levels at night) is synchronized by the prevailing light:dark environment with the retinas of the eyes doing the photoreception required for the induction of this rhythm. The advent of artificial light sources has allowed animals or humans to be exposed to light at unusual times, i.e., during the night. Light falling on the retinas at night leads to a rapid depression in the production and secretion of melatonin by the pineal gland. The magnitude of the drop in circulating melatonin due to light exposure at night is related to the brightness (intensity) as well as the wavelength (color) of light to which humans are exposed. The lowered melatonin values following unusual light exposure at night provide erroneous information to a number of organs that respond to the melatonin message since the signal implies it is day when, in fact, it is still night. Besides visible light, certain ultraviolet wavelengths as well as extremely low frequency electric and magnetic fields may also disturb the melatonin rhythm. These nonvisible wavelengths may influence the circadian melatonin rhythm by mechanisms similar to those by which light causes disturbances of melatonin production and release.
R J Reiter
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Regulatory toxicology and pharmacology : RTP     Volume:  15     ISSN:  0273-2300     ISO Abbreviation:  Regul. Toxicol. Pharmacol.     Publication Date:  1992 Jun 
Date Detail:
Created Date:  1992-09-21     Completed Date:  1992-09-21     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  8214983     Medline TA:  Regul Toxicol Pharmacol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  226-44     Citation Subset:  IM    
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78284-7762.
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MeSH Terms
Circadian Rhythm / physiology*
Electromagnetic Fields*
Melatonin / biosynthesis,  physiology*
Norepinephrine / physiology
Pineal Gland / metabolism,  physiology*
Reg. No./Substance:
51-41-2/Norepinephrine; 73-31-4/Melatonin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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