The pituitary-thyroid axis in healthy men living under subarctic climatological conditions
In order to evaluate the effects of climatic factors on the secretion of thyroid hormones and TSH in a high latitude population, we have taken serum and urine samples from 20 healthy men from northern Finland (67 degrees -68 degrees N) every 2 months for a period of 14 months. Serum free triiodothyr...
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Bioscientifica
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crbioscientif:10.1677/joe.0.1690195 2024-09-30T14:40:08+00:00 The pituitary-thyroid axis in healthy men living under subarctic climatological conditions Hassi, J Sikkila, K Ruokonen, A Leppaluoto, J 2001 http://dx.doi.org/10.1677/joe.0.1690195 https://joe.bioscientifica.com/view/journals/joe/169/1/195.xml https://joe.bioscientifica.com/downloadpdf/journals/joe/169/1/195.xml unknown Bioscientifica Journal of Endocrinology volume 169, issue 1, page 195-203 ISSN 0022-0795 1479-6805 journal-article 2001 crbioscientif https://doi.org/10.1677/joe.0.1690195 2024-09-12T04:13:13Z In order to evaluate the effects of climatic factors on the secretion of thyroid hormones and TSH in a high latitude population, we have taken serum and urine samples from 20 healthy men from northern Finland (67 degrees -68 degrees N) every 2 months for a period of 14 months. Serum free triiodothyronine (T(3)) levels were lower in February than in August (3.9 vs 4.4 pmol/l, P<0.05) and TSH levels were higher in December than during other months (2.1 vs 1.5-1.7 mU/l, P<0.01). Serum total and free thyroxine (T(4)), total T(3) and reverse T(3) levels and urinary T(4) levels were unchanged. Urinary T(3) levels were significantly higher in winter than in summer. Serum free T(3) correlated highly significantly with the outdoor temperature integrated backwards weekly for 7-56 days (r=0.26 for 1-56 days) from the day when the blood samples were taken. Serum TSH did not show any significant correlation with the thyroid hormones or with the integrated temperature of the previous days, but it did show an inverse and significant correlation (r=-0.31) with the ambient luminosity integrated backwards for 7 days from the day when the blood sample was taken. The gradually increasing correlation between outdoor temperatures and serum free T(3) suggests that the disposal of thyroid hormones is accelerated in winter, leading to low serum free T(3) levels and a high urinary free T(3) excretion. Since there was no correlation between thyroid hormones and serum TSH, the feedback mechanism between TSH and thyroid hormones may not be the only contributing factor, and other factors such as ambient luminosity may at least partly determine serum TSH in these conditions. Also urinary free T(3) appears to be a novel and non-invasive indicator for thyroid physiology. Article in Journal/Newspaper Northern Finland Subarctic Bioscientifica Journal of Endocrinology 169 1 195 203 |
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In order to evaluate the effects of climatic factors on the secretion of thyroid hormones and TSH in a high latitude population, we have taken serum and urine samples from 20 healthy men from northern Finland (67 degrees -68 degrees N) every 2 months for a period of 14 months. Serum free triiodothyronine (T(3)) levels were lower in February than in August (3.9 vs 4.4 pmol/l, P<0.05) and TSH levels were higher in December than during other months (2.1 vs 1.5-1.7 mU/l, P<0.01). Serum total and free thyroxine (T(4)), total T(3) and reverse T(3) levels and urinary T(4) levels were unchanged. Urinary T(3) levels were significantly higher in winter than in summer. Serum free T(3) correlated highly significantly with the outdoor temperature integrated backwards weekly for 7-56 days (r=0.26 for 1-56 days) from the day when the blood samples were taken. Serum TSH did not show any significant correlation with the thyroid hormones or with the integrated temperature of the previous days, but it did show an inverse and significant correlation (r=-0.31) with the ambient luminosity integrated backwards for 7 days from the day when the blood sample was taken. The gradually increasing correlation between outdoor temperatures and serum free T(3) suggests that the disposal of thyroid hormones is accelerated in winter, leading to low serum free T(3) levels and a high urinary free T(3) excretion. Since there was no correlation between thyroid hormones and serum TSH, the feedback mechanism between TSH and thyroid hormones may not be the only contributing factor, and other factors such as ambient luminosity may at least partly determine serum TSH in these conditions. Also urinary free T(3) appears to be a novel and non-invasive indicator for thyroid physiology. |
format |
Article in Journal/Newspaper |
author |
Hassi, J Sikkila, K Ruokonen, A Leppaluoto, J |
spellingShingle |
Hassi, J Sikkila, K Ruokonen, A Leppaluoto, J The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
author_facet |
Hassi, J Sikkila, K Ruokonen, A Leppaluoto, J |
author_sort |
Hassi, J |
title |
The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
title_short |
The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
title_full |
The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
title_fullStr |
The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
title_full_unstemmed |
The pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
title_sort |
pituitary-thyroid axis in healthy men living under subarctic climatological conditions |
publisher |
Bioscientifica |
publishDate |
2001 |
url |
http://dx.doi.org/10.1677/joe.0.1690195 https://joe.bioscientifica.com/view/journals/joe/169/1/195.xml https://joe.bioscientifica.com/downloadpdf/journals/joe/169/1/195.xml |
genre |
Northern Finland Subarctic |
genre_facet |
Northern Finland Subarctic |
op_source |
Journal of Endocrinology volume 169, issue 1, page 195-203 ISSN 0022-0795 1479-6805 |
op_doi |
https://doi.org/10.1677/joe.0.1690195 |
container_title |
Journal of Endocrinology |
container_volume |
169 |
container_issue |
1 |
container_start_page |
195 |
op_container_end_page |
203 |
_version_ |
1811642669286293504 |