科研之友
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摘要
P>Objective We examined the effects of a combined levothyroxine/liothyronine supplement and exposure to bright (10,000 lux) light in euthyroid men and women who spent the austral summer (n = 43) and/or winter (n = 42) in Antarctica. Methods Subjects were randomized to receive 64 nmol of levothyroxine and 16 nmol of liothyronine supplement or a placebo capsule for 93 center dot 2 +/- 3 center dot 0 days in summer and/or 149 center dot 5 +/- 2 center dot 2 days in winter. Subjects were further randomized to receive 10,000 lux bright white light or 50 lux dim red light for 14 days at the end of summer and/or winter. Cognitive performance and mood were assessed using the Automatic Neuropsychological Assessment Metric - Isolated and Confined Environments. Results In winter, bright light exposure was associated with a significantly greater reduction in TSH and anger (P < 0 center dot 05), a significantly greater increase in fT(3) (P < 0 center dot 05), and a significantly smaller increase in depressive symptoms (P < 0 center dot 001), when compared with dim light. The T4/T3 supplement also led to a significantly greater reduction in TSH (P < 0 center dot 05), but a greater reduction in cognitive task efficiency (P < 0 center dot 05) as well, when compared with placebo. Conclusion Administration of bright light leads to a significant reduction in serum TSH and prevents increases in anger and depressive symptoms in winter. However, these associations were not observed in summer, suggesting a seasonal influence of photoperiod over temperature upon this intervention in the polar environment.
- 出版日期2010-4
