Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study

Summary Objective Seasonal variation in photoperiod or temperature may influence human reproductive biology. The present study evaluated whether seasonal changes occurred in the levels of reproductive hormones and the major melatonin metabolite, 6‐sulfatoxymelatonin (aMT6s), in populations exposed t...

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Published in:Clinical Endocrinology
Main Authors: Ruhayel, Yasir, Malm, Gunilla, Haugen, Trine B., Henrichsen, Trine, Bjørsvik, Cathrine, Grotmol, Tom, Sæther, Thomas, Malm, Johan, Figenschau, Yngve, Rylander, Lars, Levine, Richard J., Giwercman, Aleksander
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2007
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Online Access:http://dx.doi.org/10.1111/j.1365-2265.2007.02843.x
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2265.2007.02843.x
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spelling crwiley:10.1111/j.1365-2265.2007.02843.x 2024-06-02T08:02:03+00:00 Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study Ruhayel, Yasir Malm, Gunilla Haugen, Trine B. Henrichsen, Trine Bjørsvik, Cathrine Grotmol, Tom Sæther, Thomas Malm, Johan Figenschau, Yngve Rylander, Lars Levine, Richard J. Giwercman, Aleksander 2007 http://dx.doi.org/10.1111/j.1365-2265.2007.02843.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2265.2007.02843.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2265.2007.02843.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Clinical Endocrinology volume 67, issue 1, page 85-92 ISSN 0300-0664 1365-2265 journal-article 2007 crwiley https://doi.org/10.1111/j.1365-2265.2007.02843.x 2024-05-03T10:50:08Z Summary Objective Seasonal variation in photoperiod or temperature may influence human reproductive biology. The present study evaluated whether seasonal changes occurred in the levels of reproductive hormones and the major melatonin metabolite, 6‐sulfatoxymelatonin (aMT6s), in populations exposed to extreme variation in photoperiod and temperature. Design Two separate cohorts of Norwegian men were recruited from the general population in either of two locations: Tromsø (69·5°N, n = 92) or Oslo (60°N, n = 112), located north and south of the Arctic Circle (66·5°N), respectively. Measurements Four blood and 12‐h overnight urine samples were obtained on separate occasions over a 12‐month period, including during the photoperiod maximum and minimum. Serum concentrations of FSH, LH, testosterone (T), oestradiol (E 2 ), SHBG and the urinary excretion of aMT6s were assessed. Results Statistical analysis using generalized estimating equations indicated that LH levels were lowest during early winter in both locations (both P = 0·01). In Tromsø, free T and E 2 concentrations peaked during early winter ( P = 0·02 and 0·003, respectively). In Oslo, free T levels were lowest during early winter ( P = 0·06) whereas E 2 levels were lowest during late summer ( P < 0·001). Urinary aMT6s concentrations were lowest during early summer in Tromsø and Oslo. Concentrations peaked during early winter in Tromsø ( P < 0·001) and during late winter in Oslo ( P < 0·001). Conclusions LH levels exhibited similar changes in both locations, whereas the patterns of changes of the sex steroid concentrations differed, possibly indicating different underlying mechanisms. Excretion of aMT6s was lowest during early summer in both locations, indicating that the long natural photoperiod was sufficient to cause suppression of melatonin secretion. Whether these changes have any biological significance remains uncertain. Article in Journal/Newspaper Arctic Tromsø Wiley Online Library Arctic Tromsø Clinical Endocrinology 67 1 85 92
institution Open Polar
collection Wiley Online Library
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language English
description Summary Objective Seasonal variation in photoperiod or temperature may influence human reproductive biology. The present study evaluated whether seasonal changes occurred in the levels of reproductive hormones and the major melatonin metabolite, 6‐sulfatoxymelatonin (aMT6s), in populations exposed to extreme variation in photoperiod and temperature. Design Two separate cohorts of Norwegian men were recruited from the general population in either of two locations: Tromsø (69·5°N, n = 92) or Oslo (60°N, n = 112), located north and south of the Arctic Circle (66·5°N), respectively. Measurements Four blood and 12‐h overnight urine samples were obtained on separate occasions over a 12‐month period, including during the photoperiod maximum and minimum. Serum concentrations of FSH, LH, testosterone (T), oestradiol (E 2 ), SHBG and the urinary excretion of aMT6s were assessed. Results Statistical analysis using generalized estimating equations indicated that LH levels were lowest during early winter in both locations (both P = 0·01). In Tromsø, free T and E 2 concentrations peaked during early winter ( P = 0·02 and 0·003, respectively). In Oslo, free T levels were lowest during early winter ( P = 0·06) whereas E 2 levels were lowest during late summer ( P < 0·001). Urinary aMT6s concentrations were lowest during early summer in Tromsø and Oslo. Concentrations peaked during early winter in Tromsø ( P < 0·001) and during late winter in Oslo ( P < 0·001). Conclusions LH levels exhibited similar changes in both locations, whereas the patterns of changes of the sex steroid concentrations differed, possibly indicating different underlying mechanisms. Excretion of aMT6s was lowest during early summer in both locations, indicating that the long natural photoperiod was sufficient to cause suppression of melatonin secretion. Whether these changes have any biological significance remains uncertain.
format Article in Journal/Newspaper
author Ruhayel, Yasir
Malm, Gunilla
Haugen, Trine B.
Henrichsen, Trine
Bjørsvik, Cathrine
Grotmol, Tom
Sæther, Thomas
Malm, Johan
Figenschau, Yngve
Rylander, Lars
Levine, Richard J.
Giwercman, Aleksander
spellingShingle Ruhayel, Yasir
Malm, Gunilla
Haugen, Trine B.
Henrichsen, Trine
Bjørsvik, Cathrine
Grotmol, Tom
Sæther, Thomas
Malm, Johan
Figenschau, Yngve
Rylander, Lars
Levine, Richard J.
Giwercman, Aleksander
Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
author_facet Ruhayel, Yasir
Malm, Gunilla
Haugen, Trine B.
Henrichsen, Trine
Bjørsvik, Cathrine
Grotmol, Tom
Sæther, Thomas
Malm, Johan
Figenschau, Yngve
Rylander, Lars
Levine, Richard J.
Giwercman, Aleksander
author_sort Ruhayel, Yasir
title Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
title_short Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
title_full Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
title_fullStr Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
title_full_unstemmed Seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the Arctic Circle: a longitudinal study
title_sort seasonal variation in serum concentrations of reproductive hormones and urinary excretion of 6‐sulfatoxymelatonin in men living north and south of the arctic circle: a longitudinal study
publisher Wiley
publishDate 2007
url http://dx.doi.org/10.1111/j.1365-2265.2007.02843.x
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2265.2007.02843.x
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2265.2007.02843.x
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op_source Clinical Endocrinology
volume 67, issue 1, page 85-92
ISSN 0300-0664 1365-2265
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op_doi https://doi.org/10.1111/j.1365-2265.2007.02843.x
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