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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 LU ; Malm, Gunilla LU ; Haugen, Trine B; Henrichsen, Trine; Bjorsvik, Cathrine; Grotmol, Tom; Sæther, Thomas; Malm, Johan LU ; Figenschau, Yngve and Rylander, Lars LU , et al. (2007) In Clinical Endocrinology 67(1). p.85-92
Abstract
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... (More)
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. (Less)
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Clinical Endocrinology
volume
67
issue
1
pages
85 - 92
publisher
Wiley-Blackwell
external identifiers
  • wos:000247339300013
  • scopus:34250727149
ISSN
1365-2265
DOI
10.1111/j.1365-2265.2007.02843.x
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English
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yes
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03b7866a-70ff-4a21-b9c7-a7c580dbd343 (old id 540020)
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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=17547693&dopt=Abstract
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2007-12-21 13:43:30
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2017-01-22 03:27:55
@article{03b7866a-70ff-4a21-b9c7-a7c580dbd343,
  abstract     = {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 &lt; 0.001). Urinary aMT6s concentrations were lowest during early summer in Tromso and Oslo. Concentrations peaked during early winter in Tromso (P &lt; 0.001) and during late winter in Oslo (P &lt; 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.},
  author       = {Ruhayel, Yasir and Malm, Gunilla and Haugen, Trine B and Henrichsen, Trine and Bjorsvik, Cathrine and Grotmol, Tom and Sæther, Thomas and Malm, Johan and Figenschau, Yngve and Rylander, Lars and Levine, Richard J and Giwercman, Aleksander},
  issn         = {1365-2265},
  language     = {eng},
  number       = {1},
  pages        = {85--92},
  publisher    = {Wiley-Blackwell},
  series       = {Clinical Endocrinology},
  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.},
  url          = {http://dx.doi.org/10.1111/j.1365-2265.2007.02843.x},
  volume       = {67},
  year         = {2007},
}