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Human cold air habituation is independent of thyroxine and thyrotropin


, : Human cold air habituation is independent of thyroxine and thyrotropin. Journal of Applied Physiology 72(6): 2134-2139

Thyroxine (T4) is required in species possessing brown adipose tissue (BAT) for the maintenance of cold tolerance and adaptation. In humans, who possess negligible quantities of BAT, the importance of T4 has not been demonstrated. We studied the effects of decreased serum T4 and thyrotropin (TSH) on human cold habituation after repeated cold air exposures. Eight men (T3+) received a single daily dose of triiodothyronine (T3; 30 .mu.g/day), and another eight men (T3-) received a placebo. All 16 normal thyroid men underwent a standardized cold air test (SCAT) under basal conditions in January and again in March after eighty 30-min 4.4.degree.C air exposures (10/wk). Measurements of basal metabolic rate (BMR), O2 consumption (.ovrhdot.VO2), mean arterial pressure (MAP), plasma norepinephrine (NE), serum TSH, free and total T4, and free and total T3 were repeated before and after 8 wk of exposure. TSH, free T4, and total T4 were 50% lower for T3+ than for T3- subjects. Total and free T3 were not different between groups. BMR was unchanged after habituation, whereas the cold-stimulated .ovrhdot.VO2 MAP, and NE were significantly reduced for all subjects in March. The relationship between .ovrhdot.VO2 and NE (r2 = 0.44, P < 0.001) during the initial SCAT was unchanged with habituation. We suggest that human cold habituation is independent of major changes in circulating T4 and TSH.

US$29.90

PMID: 1629066


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Reford Stephen, 2006: Gradient enhancement of the total magnetic field. The collection of magnetic gradiometer data using a configuration of two, three, or four magnetometers has become commonplace. One use of these data is to improve the accuracy and resolution of the gridded total magnetic field beyond what can be i...

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Tatole, V., 1990: The structure of polytene chromosomes from the salivary glands of Propsilocerus danubialis Botnariuc and Albu (Diptera, Chironomidae). The polytene chromosomes of P. danubialis, a Ponto-Caspian relict from the Danube delta, were studied. The karyotype had 2 n = 6 long, metacentric chromosomes. No inversions, but many active chromosome regions (nucleoli, Balbiani rings and puffs)...

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Gao J.; O.L.ary S.M., 1997: Estimation of suspended solids from aerial photographs in a GIS. International Journal of Remote Sensing 18(10): 2073-2086

Rankin, M., 2014: Can one be two? A synopsis of the twinning and personhood debate. It has been argued that the possibility of monozygotic twinning disproves the conservative position on foetal personhood that defines the foetus as a person from conception. This article will canvass arguments for and against this proposition, in...

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Taubmann, G., 1952: Mechanism of the effect of pine-needle bath. Munchener Medizinische Wochenschrift 94(11): 500-501