Thyroid response to blocking sympathetic activity in chronic cold-exposed hunters in East Greenland: a case–control study
Authors' conclusion
We hypothesise that when blocking the sympathetic system, TSH increases to uphold the production of T3 needed for maintaining BAT activity. Additionally, alterations of fT3/fT4-ratio support a hypothesis of adrenergic stimulation promoting T3 over T4 secretion from the thyroid via the adrenergic nerve terminals in the thyroid.
Study context
- Population
- Healthy men, Greenlandic hunters and non-hunters, East Greenland in winter
- Participants
- 7 vs 8
- Comparison
- Hunters vs non-hunter Greenlanders (controls); hunters given a non-selective beta blocker for 7 days
- Huntersn = 7
- Controlsn = 8reference
- Outcome
- TSH, thyroid hormones and Tg
Methodological details7-day field study, East Greenland, February, Blood samples drawn daily
- 7-day field study
- East Greenland, February
- Blood samples drawn daily
Main finding
As reported in the abstract
- Hunters had higher serum Tg, TSH and high fT3/fT4 ratio vs controls
- Sympathetic blockade: serum Tg and fT3 initially decreased, then restored
- Sympathetic blockade: TSH and fT4 gradually increased over the study
- Sympathetic blockade: fT3/fT4 ratio continuous, marked decrease
Original publication
Thyroid response to blocking sympathetic activity in chronic cold-exposed hunters in East Greenland: a case–control study. Eur Thyroid J. Published 10 December 2024. doi:10.
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