Document Detail

Effects of continuous light exposure on antioxidant enzymes, porphyric enzymes and cellular damage in the Harderian gland of the Syrian hamster.
MedLine Citation:
PMID:  12485373     Owner:  NLM     Status:  MEDLINE    
The Syrian hamster Harderian gland (HG), an organ present in the male two secretory cell types (type-I and type-II cells), is physiologically exposed to high oxidative stress because of high concentrations of porphyrins and their precursor, 5-aminolevulinic acid. Because of its juxtaorbital location, the HG is accessible to light, and subject to phototoxic effects of these substances. After having previously demonstrated circadian rhythms in antioxidant enzymes, porphyric enzymes and oxidative damage of proteins and lipids, as well as influences of melatonin on these parameters, we have now studied the effects of continuous light (LL), which suppresses melatonin secretion by the pineal gland. Measurements were performed in two different circadian phases, in order to detect the presence or absence of day/night differences. In LL, no differences between circadian phases of subjective day and subjective night were demonstrable for 5-aminolevulinate synthase, 5-aminolevulinate dehydratase, porphobilinogen deaminase, or superoxide dismutase; temporal differences in glutathione reductase and catalase were markedly diminished, whereas all these parameters showed marked day/night differences in the rats exposed to a light/dark cycle of 14:10. In LL, oxidative damage to lipids was minimally effected, while protein damage was enhanced. LL also caused a reduction in the percentage of type-II cells. Therefore, cell differentiation in the HG does not seem to be controlled only by the androgen, but, unexpectedly, also by melatonin.
Cristina Tomás-Zapico; Ana Coto-Montes; Jorge Martínez-Fraga; María Josefa Rodríguez-Colunga; Delio Tolivia
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of pineal research     Volume:  34     ISSN:  0742-3098     ISO Abbreviation:  J. Pineal Res.     Publication Date:  2003 Jan 
Date Detail:
Created Date:  2002-12-17     Completed Date:  2003-07-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8504412     Medline TA:  J Pineal Res     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  60-8     Citation Subset:  IM    
Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain.
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MeSH Terms
Catalase / radiation effects*
Circadian Rhythm / physiology,  radiation effects
Glutathione Reductase / radiation effects*
Harderian Gland / physiology*
Heme / biosynthesis
Porphyrins / biosynthesis*
Superoxide Dismutase / radiation effects*
Reg. No./Substance:
0/Porphyrins; 14875-96-8/Heme; EC; EC Dismutase; EC Reductase

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