Document Detail

Melatonin synthesis in the retina and pineal gland of Djungarian hamsters at different times of the year.
MedLine Citation:
PMID:  8520463     Owner:  NLM     Status:  MEDLINE    
Daily profiles of melatonin content in the retina of Djungarian hamsters were measured throughout the course of a year. Peak levels of retinal melatonin were found at various times of the day at different seasons. In a subsequent study we determined concurrently daily profiles of nine indole metabolites (tryptophan, 5-hydroxytryptophan, 5-hydroxytryptamin, 5-hydroxyindoleacetic acid, 5-hydroxytryptophol, N-acetylserotonin, melatonin, 5-methoxyindoleacetic acid and 5-methoxytryptophol) in samples of hamster retina and pineal gland at the four different seasons. Measurements were made using HPLC coupled to a coulometric electrode detection system. Large seasonal variations in the levels and daily rhythm amplitudes of the different indole metabolites were found in the pineal glands. Due to technical problems and unknown interfering substances only tryptophan and serotonin could be determined in the retinas at all four seasons. Despite this, the ability to measure levels of several metabolites in the same sample and in different tissues of the same animals permitted more accurate comparisons of the components involved in melatonin synthesis. Our data suggest that the level of retinal melatonin is regulated and controlled locally within the retina itself. However, long-term feedback mechanisms from other sources of melatonin are not excluded but are rather likely.
S Steinlechner; I Baumgartner; G Klante; R J Reiter
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neurochemistry international     Volume:  27     ISSN:  0197-0186     ISO Abbreviation:  Neurochem. Int.     Publication Date:  1995 Sep 
Date Detail:
Created Date:  1996-01-19     Completed Date:  1996-01-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8006959     Medline TA:  Neurochem Int     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  245-51     Citation Subset:  IM    
Department of Zoology, School of Veterinary Medicine, Hannover, Germany.
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MeSH Terms
Chromatography, High Pressure Liquid
Circadian Rhythm*
Melatonin / biosynthesis*
Pineal Gland / metabolism*,  physiology
Retina / metabolism*,  physiology
Serotonin / metabolism
Tryptophan / metabolism
Reg. No./Substance:
50-67-9/Serotonin; 73-22-3/Tryptophan; 73-31-4/Melatonin

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