Pituitary-Gonadal Response to Extreme Cold Exposure in Healthy Men

Solter, Miljenko; Misjak, Mira

doi:10.1055/s-2007-1009232

Cited by 6 publications

(7 citation statements)

References 4 publications

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“…However, these findings are not in agreement with the observations of Solter and Misjak (1989), who observed a decline in testosterone, oestradiol, PRL and LH in men exposed to intermittent cold at −40°C and −20°C (1 h of exposure alternating with 1 h of rest) in a meat-processing factory. We have no explanation for the discrepancy between our findings and those of Solter and Misjak (1989) except that in our study the hormonal investigtions were carried out in tropical men who were continuously exposed to the Antarctic environment for prolonged durations. Alternatively, these changes in testosterone in Antarctica could also be due to circannual variations of the hormone at the polar latitude.…”

Section: Discussioncontrasting

confidence: 99%

Pituitary-gonadal hormones during prolonged residency in Antarctica

Sawhney

Malhotra

Prasad

et al. 1998

International Journal of Biometeorology

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Plasma luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL) and testosterone levels were measured in nine eugonadal men in New Delhi and during the 1st week of different months of their stay at Dakshin Gangotri in Antarctica. During their 12-month stay in Antarctica, they were exposed to a severely cold climate, long polar nights and polar days, high wind velocity, increased amounts of solar and ultraviolet radiation and geomagnetism, as well as physical and social isolation. Plasma testosterone tended to increase in March, but a significant increase (P < 0.05) was not seen until April. The mean testosterone levels in May, June, September and November were also significantly higher than the March or New Delhi values. The absolute values of LH, FSH and PRL did not show any month-to-month changes in Antarctica. However, when the hormone levels were expressed as a percentage of the individual annual Antarctic mean, significant differences as a percentage of the individual annual Antarctic mean, significant differences were observed. The testosterone peak in April, May and June was associated with an increase in LH. The nadirs of testosterone, LH, FSH and PRL were seen in either July or August. FSH showed the highest values in March, whereas the highest PRL values were seen in November. These observations suggest the presence of circannual variations in gonadotropin, PRL and LH in Antarctica which are independent of polar days and polar nights. It appears that factors other than the duration of daylight might be involved in regulating these changes. The significance of maintenance of testosterone levels in the supra-physiological range in Antarctica remains unknown but may be important in acclimatization/habituation to the extreme polar cold by increasing basal metabolic rate, protein synthesis and erythropoiesis.

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Section: Discussioncontrasting

confidence: 99%

Pituitary-gonadal hormones during prolonged residency in Antarctica

Sawhney

Malhotra

Prasad

et al. 1998

International Journal of Biometeorology

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“…In meat factory workers staying below -20º C for several hours serum total T4 and T3 decreased. In other workers staying daily in temperatures between -10 and 8º C total T4 did not change, total T3 decreased, but unexpectedly free T3 increased (10).…”

Section: Thyroid Hormonesmentioning

confidence: 76%

“…An acute cold air exposure of from 15 min to 2 h at 4 -13º C decreased the plasma PRL levels (3,36,49). In meat factory workers staying daily between -40 and 8º C plasma PRL decreased (10). Exposing face to cold air during bicycle exercise increased plasma PRL less than in controls (50).…”

Section: Growth Hormone and Prolactinmentioning

confidence: 93%

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Cold exposure and hormonal secretion: A review

Pääkkönen¹,

Leppäluoto

2002

International Journal of Circumpolar Health

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“…Cold exposures have no effects or inhibitory effects on gonadotropins, testosterone or oestrogens (Leppäluoto et al. 1988, Solter & Misjak 1989). Leptin, a hormone secreted by adipose tissues, inhibits feeding behaviour and stimulates metabolism and heat production, e.g.…”

Section: Other Hormones During Cold Exposuresmentioning

confidence: 99%

Pituitary and autonomic responses to cold exposures in man

Leppäluoto

Pääkkönen

Korhonen

et al. 2005

Acta Physiologica Scandinavica

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This review presents hormonal responses to various cold exposures and their calorigenic effects in man and some animals. Previous studies in rats have shown that cold exposures activate the hypothalamic-pituitary-thyroid axis. Increased thyroid hormone concentrations lead to heat production via general stimulation of metabolism (obligatory thermogenesis) and possibly via activation of thyroid hormone receptors and uncoupling protein 1 (UCP 1) and deiodinase enzyme genes in the brown adipose tissue (BAT). In human subjects long-term cold exposures do not seem to activate the pituitary-thyroid axis, but rather accelerate the elimination of triiodothyronine (T3), leading to low serum concentrations of free T3 hormone. In corollary to this a hypothyreotic condition with increased serum thyroid-stimulating hormone and impaired mood and cognitive performance can be observed after long-term cold exposures such as wintering. During cold exposures the sympathetic nerve system is activated and noradrenaline is released to blood circulation and to BAT, where it leads to production of cAMP, lipolysis and free fatty acids. Free fatty acids open the mitochondrial proton channel protein in BAT. Protons enter the mitochondria and inhibit ATP synthesis (uncoupling). By this way energy is transformed into heat (facultatory or adaptive thermogenesis). In adult human subjects the amount of BAT is small and adaptive thermogenesis (non-shivering thermogenesis) has a smaller role. UCP 1 with other uncoupling proteins may have other functions in the control of body weight, sugar balance and formation of reactive oxygen species.

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Pituitary-Gonadal Response to Extreme Cold Exposure in Healthy Men

Cited by 6 publications

References 4 publications

Pituitary-gonadal hormones during prolonged residency in Antarctica

Pituitary-gonadal hormones during prolonged residency in Antarctica

Cold exposure and hormonal secretion: A review

Pituitary and autonomic responses to cold exposures in man

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