Document Detail

Urinary 6-sulphatoxymelatonin excretory rhythms in laboratory rats: effects of photoperiod and light.
MedLine Citation:
PMID:  8461986     Owner:  NLM     Status:  MEDLINE    
The excretion rhythm of the melatonin metabolite, 6-sulphatoxymelatonin, was determined in rats maintained on contrasting 14 h L:10 h D and 10 h L:14 h D photoperiods. The novel use of a high protein liquid diet together with an automatic urine collection system facilitated the monitoring of the onset, offset and total production of metabolite before, during and after a 57.5% reduction in the dark period (5.75 h and 8 h delay in lights off). In 14 L:10 D, melatonin metabolite excretion increased 2.7 +/- 0.2 h after lights off, whereas in 10 L:14 D, the onset occurred 5.1 +/- 0.2 h after lights off. Duration of melatonin metabolite excretion was not different between the two photoperiods. Reduction of the dark period by 57.5% delayed the appearance of melatonin metabolite excretion until 2.15 +/- 0.4h and 2.9 +/- 0.4h after darkness in both long and short photoperiods. Upon restoration of the original photoperiod on the third day, the onset of metabolite excretion was significantly delayed by 1.4 +/- 0.4 h (P < 0.05) in long day animals and 2.2 +/- 0.2 h (P < 0.05) in short day-length compared to the first day. This study highlights the utility of urinary 6-sulphatoxymelatonin determinations in rats and provides new information on the acute effects of extended evening light on pineal melatonin secretion.
D J Kennaway
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Brain research     Volume:  603     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  1993 Feb 
Date Detail:
Created Date:  1993-05-03     Completed Date:  1993-05-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  338-42     Citation Subset:  IM    
Department of Obstetrics and Gynaecology, University of Adelaide, Australia.
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MeSH Terms
Circadian Rhythm*
Melatonin / analogs & derivatives*,  urine
Rats, Wistar
Reg. No./Substance:
2208-40-4/6-sulfatoxymelatonin; 73-31-4/Melatonin

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