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Seasonal variation ...
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.
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- Ruhayel, Yasir (author)
- Lund University,Lunds universitet,Institutionen för kliniska vetenskaper, Malmö,Medicinska fakulteten,Department of Clinical Sciences, Malmö,Faculty of Medicine
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- Malm, Gunilla (author)
- Lund University,Lunds universitet,Institutionen för kliniska vetenskaper, Malmö,Medicinska fakulteten,Department of Clinical Sciences, Malmö,Faculty of Medicine
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Haugen, Trine B (author)
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Henrichsen, Trine (author)
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Bjorsvik, Cathrine (author)
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Grotmol, Tom (author)
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Sæther, Thomas (author)
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- Malm, Johan (author)
- Lund University,Lunds universitet,Klinisk kemi, Malmö,Forskargrupper vid Lunds universitet,Clinical Chemistry, Malmö,Lund University Research Groups
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Figenschau, Yngve (author)
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- Rylander, Lars (author)
- Lund University,Lunds universitet,Avdelningen för arbets- och miljömedicin,Institutionen för laboratoriemedicin,Medicinska fakulteten,Division of Occupational and Environmental Medicine, Lund University,Department of Laboratory Medicine,Faculty of Medicine
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Levine, Richard J (author)
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- Giwercman, Aleksander (author)
- Lund University,Lunds universitet,Reproduktionsmedicin, Malmö,Forskargrupper vid Lunds universitet,Reproductive medicine, Malmö,Lund University Research Groups
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(creator_code:org_t)
- Wiley, 2007
- 2007
- English.
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In: Clinical Endocrinology. - : Wiley. - 1365-2265 .- 0300-0664. ; 67:1, s. 85-92
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http://dx.doi.org/10...
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Abstract
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- bjective 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: Tromso (69.5 degrees N, n = 92) or Oslo (60 degrees N, n = 112), located north and south of the Arctic Circle (66.5 degrees 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 Tromso, 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 Tromso and Oslo. Concentrations peaked during early winter in Tromso (P < 0.001) and during late winter in Oslo (P < 0.001). Conclusion 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.
Subject headings
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)
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- art (subject category)
- ref (subject category)
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- By the author/editor
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Ruhayel, Yasir
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Malm, Gunilla
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Haugen, Trine B
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Henrichsen, Trin ...
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Bjorsvik, Cathri ...
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Grotmol, Tom
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Sæther, Thomas
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Malm, Johan
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Figenschau, Yngv ...
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Rylander, Lars
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Levine, Richard ...
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Giwercman, Aleks ...
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- MEDICAL AND HEALTH SCIENCES
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MEDICAL AND HEAL ...
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and Endocrinology an ...
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Clinical Endocri ...
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Lund University