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Dim light at night disrupts the short-day response in Siberian hamsters.
- Source :
-
General and comparative endocrinology [Gen Comp Endocrinol] 2014 Feb 01; Vol. 197, pp. 56-64. Date of Electronic Publication: 2013 Dec 19. - Publication Year :
- 2014
-
Abstract
- Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response.<br /> (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Subjects :
- Animals
Circadian Rhythm radiation effects
Gene Expression Regulation physiology
Gene Expression Regulation radiation effects
Gonadotropin-Releasing Hormone genetics
Hypothalamic Hormones genetics
Immune System radiation effects
Lipopolysaccharides pharmacology
Male
Motor Activity physiology
Motor Activity radiation effects
Phodopus genetics
Protein Tyrosine Phosphatases genetics
Receptors, Melatonin genetics
Reproduction physiology
Reproduction radiation effects
Seasons
Spermatids physiology
Spermatozoa physiology
Circadian Rhythm physiology
Immune System physiology
Light
Phodopus physiology
Photoperiod
Subjects
Details
- Language :
- English
- ISSN :
- 1095-6840
- Volume :
- 197
- Database :
- MEDLINE
- Journal :
- General and comparative endocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 24362257
- Full Text :
- https://doi.org/10.1016/j.ygcen.2013.12.005