Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus )
The purpose of this study was to examine the effect of photoperiod on serum levels of growth hormone (GH) and thyroid hormones (TH), body mass, and body composition in collared lemmings (Dicrostonyx groenlandicus). Collared lemmings undergo seasonal changes in body mass and body composition, being h...
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1994
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Online Access: | http://dx.doi.org/10.1139/z94-233 http://www.nrcresearchpress.com/doi/pdf/10.1139/z94-233 |
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crcansciencepubl:10.1139/z94-233 2023-12-17T10:29:24+01:00 Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) Nagy, Tim R. Gower, Barbara A. Stetson, Milton H. 1994 http://dx.doi.org/10.1139/z94-233 http://www.nrcresearchpress.com/doi/pdf/10.1139/z94-233 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 72, issue 10, page 1726-1734 ISSN 0008-4301 1480-3283 Animal Science and Zoology Ecology, Evolution, Behavior and Systematics journal-article 1994 crcansciencepubl https://doi.org/10.1139/z94-233 2023-11-19T13:38:27Z The purpose of this study was to examine the effect of photoperiod on serum levels of growth hormone (GH) and thyroid hormones (TH), body mass, and body composition in collared lemmings (Dicrostonyx groenlandicus). Collared lemmings undergo seasonal changes in body mass and body composition, being heavier, but relatively less fat, during the winter months. These physiological changes can be induced in the laboratory by exposure to short photoperiod. The present study tests the hypothesis that photoperiod-mediated changes in GH and TH occur simultaneously with, and therefore may regulate or be permissive to, changes in body mass and body composition. Juvenile (19 d of age) or adult (50 d of age) male collared lemmings reared in long photoperiod (LD), 22 h light (L): 2 h dark (D), either remained in LD or were transferred to short photoperiod (SD), 8 h L: 16 h D. After 1, 2, 3, and 4 weeks (juveniles) or 1 and 3 weeks (adults) of treatment, animals were sacrificed. Serum levels of GH, triiodothyronine, and thyroxine were determined. Carcasses were weighed and analyzed for absolute and relative (analysis of covariance) fat-free dry mass, fat, and water. Exposure to SD resulted in an increase in GH, a decrease in TH, an increase in body mass (due to an absolute increase in all body components), a relative decrease in fat mass, and a relative increase in body water. Results are compatible with the hypothesis that a SD-mediated increase in GH is involved in the greater body mass gain observed in SD animals. Decreases in TH resulting from SD exposure, if associated with a decrease in heat production, may be permissive to mass gain. Article in Journal/Newspaper Dicrostonyx groenlandicus Canadian Science Publishing (via Crossref) Canadian Journal of Zoology 72 10 1726 1734 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics Nagy, Tim R. Gower, Barbara A. Stetson, Milton H. Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
topic_facet |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
description |
The purpose of this study was to examine the effect of photoperiod on serum levels of growth hormone (GH) and thyroid hormones (TH), body mass, and body composition in collared lemmings (Dicrostonyx groenlandicus). Collared lemmings undergo seasonal changes in body mass and body composition, being heavier, but relatively less fat, during the winter months. These physiological changes can be induced in the laboratory by exposure to short photoperiod. The present study tests the hypothesis that photoperiod-mediated changes in GH and TH occur simultaneously with, and therefore may regulate or be permissive to, changes in body mass and body composition. Juvenile (19 d of age) or adult (50 d of age) male collared lemmings reared in long photoperiod (LD), 22 h light (L): 2 h dark (D), either remained in LD or were transferred to short photoperiod (SD), 8 h L: 16 h D. After 1, 2, 3, and 4 weeks (juveniles) or 1 and 3 weeks (adults) of treatment, animals were sacrificed. Serum levels of GH, triiodothyronine, and thyroxine were determined. Carcasses were weighed and analyzed for absolute and relative (analysis of covariance) fat-free dry mass, fat, and water. Exposure to SD resulted in an increase in GH, a decrease in TH, an increase in body mass (due to an absolute increase in all body components), a relative decrease in fat mass, and a relative increase in body water. Results are compatible with the hypothesis that a SD-mediated increase in GH is involved in the greater body mass gain observed in SD animals. Decreases in TH resulting from SD exposure, if associated with a decrease in heat production, may be permissive to mass gain. |
format |
Article in Journal/Newspaper |
author |
Nagy, Tim R. Gower, Barbara A. Stetson, Milton H. |
author_facet |
Nagy, Tim R. Gower, Barbara A. Stetson, Milton H. |
author_sort |
Nagy, Tim R. |
title |
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
title_short |
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
title_full |
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
title_fullStr |
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
title_full_unstemmed |
Photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( Dicrostonyx groenlandicus ) |
title_sort |
photoperiod effects on body mass, body composition, growth hormone, and thyroid hormones in male collared lemmings ( dicrostonyx groenlandicus ) |
publisher |
Canadian Science Publishing |
publishDate |
1994 |
url |
http://dx.doi.org/10.1139/z94-233 http://www.nrcresearchpress.com/doi/pdf/10.1139/z94-233 |
genre |
Dicrostonyx groenlandicus |
genre_facet |
Dicrostonyx groenlandicus |
op_source |
Canadian Journal of Zoology volume 72, issue 10, page 1726-1734 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z94-233 |
container_title |
Canadian Journal of Zoology |
container_volume |
72 |
container_issue |
10 |
container_start_page |
1726 |
op_container_end_page |
1734 |
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1785581775522627584 |