Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina)
Plasma melatonin concentration of immature male elephant seals was determined by radioimmunoassay. Comparison of concentrations during two 24-h periods, one in midsummer and one in midwinter, showed that there was a marked circadian cycle in winter which was greatly modified during the long day leng...
Published in: | Australian Journal of Biological Sciences |
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Language: | English |
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CSIRO Publishing
1979
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Online Access: | https://espace.library.uq.edu.au/view/UQ:ba241f9 |
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ftunivqespace:oai:espace.library.uq.edu.au:UQ:ba241f9 2023-05-15T16:05:15+02:00 Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) Griffiths, D. Bryden, M. M. Seamark, R. F. 1979-01-01 https://espace.library.uq.edu.au/view/UQ:ba241f9 eng eng CSIRO Publishing doi:10.1071/BI9790581 issn:0004-9417 Biotechnology Developmental Biology Animal Science and Zoology General Materials Science Genetics Molecular Biology Endocrinology Reproductive Medicine General Medicine 2700 Medicine Journal Article 1979 ftunivqespace https://doi.org/10.1071/BI9790581 2020-08-18T04:48:50Z Plasma melatonin concentration of immature male elephant seals was determined by radioimmunoassay. Comparison of concentrations during two 24-h periods, one in midsummer and one in midwinter, showed that there was a marked circadian cycle in winter which was greatly modified during the long day length of summer. It is suggested that in summer there was sufficient ambient lighting during the night hours to depress the nocturnal rise in plasma melatonin. The complexity of pineal cycles in the natural environment is stressed, and in this regard the polar regions are of particular interest due to the extreme seasonal changes in day length there. Article in Journal/Newspaper Elephant Seal Elephant Seals Mirounga leonina The University of Queensland: UQ eSpace Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) Australian Journal of Biological Sciences 32 6 581 |
institution |
Open Polar |
collection |
The University of Queensland: UQ eSpace |
op_collection_id |
ftunivqespace |
language |
English |
topic |
Biotechnology Developmental Biology Animal Science and Zoology General Materials Science Genetics Molecular Biology Endocrinology Reproductive Medicine General Medicine 2700 Medicine |
spellingShingle |
Biotechnology Developmental Biology Animal Science and Zoology General Materials Science Genetics Molecular Biology Endocrinology Reproductive Medicine General Medicine 2700 Medicine Griffiths, D. Bryden, M. M. Seamark, R. F. Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
topic_facet |
Biotechnology Developmental Biology Animal Science and Zoology General Materials Science Genetics Molecular Biology Endocrinology Reproductive Medicine General Medicine 2700 Medicine |
description |
Plasma melatonin concentration of immature male elephant seals was determined by radioimmunoassay. Comparison of concentrations during two 24-h periods, one in midsummer and one in midwinter, showed that there was a marked circadian cycle in winter which was greatly modified during the long day length of summer. It is suggested that in summer there was sufficient ambient lighting during the night hours to depress the nocturnal rise in plasma melatonin. The complexity of pineal cycles in the natural environment is stressed, and in this regard the polar regions are of particular interest due to the extreme seasonal changes in day length there. |
format |
Article in Journal/Newspaper |
author |
Griffiths, D. Bryden, M. M. Seamark, R. F. |
author_facet |
Griffiths, D. Bryden, M. M. Seamark, R. F. |
author_sort |
Griffiths, D. |
title |
Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
title_short |
Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
title_full |
Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
title_fullStr |
Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
title_full_unstemmed |
Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga Leonina) |
title_sort |
summer and winter cycles in plasma melatonin levels in the elephant seal (mirounga leonina) |
publisher |
CSIRO Publishing |
publishDate |
1979 |
url |
https://espace.library.uq.edu.au/view/UQ:ba241f9 |
long_lat |
ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Midwinter |
geographic_facet |
Midwinter |
genre |
Elephant Seal Elephant Seals Mirounga leonina |
genre_facet |
Elephant Seal Elephant Seals Mirounga leonina |
op_relation |
doi:10.1071/BI9790581 issn:0004-9417 |
op_doi |
https://doi.org/10.1071/BI9790581 |
container_title |
Australian Journal of Biological Sciences |
container_volume |
32 |
container_issue |
6 |
container_start_page |
581 |
_version_ |
1766401156712497152 |