Endocrine markers of semistarvation in healthy lean men in a multistressor environment
Endocrine markers of semistarvation in healthy lean men in a multistressor environment
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DOI：
10.1152/jappl.2000.88.5.1820
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发表时间：
2000-05-01
影响因子：
3.3
通讯作者：
Askew, EW
中科院分区：
文献类型：
--
作者：
Friedl, KE;Moore, RJ;Askew, EW
我们测试了一个假设，即半饥饿的关键内分泌反应将被削弱，只改变食物的摄入量在一个多应激环境，还包括持续的工作量，睡眠不足，热应变。在两组参加为期8周的美国陆军游骑兵课程的健康年轻男性志愿者中比较血清激素，其中四个重复的限制能量摄入和再喂养周期：第I组（n = 49）和第2组（n = 48）;能量不足平均分别为1，200和1，000千卡/天。8 wk后，I组大部分动物达到最低体脂，血清3，5，3 '-三碘甲状腺原氨酸（T-3）低于正常值（78 +/- 20 ng/dl），睾酮（T）接近阉割水平（4.5 +/- 3.9 nmol/l），胰岛素样生长因子I（IGF-I）下降一半（75 +/- 25 μ g/l），胆固醇从158 +/- 31上升至217 +/- 39 mg/dl。生物可利用的T3和T进一步减少，增加其特异性结合蛋白，以响应胰岛素下降。再喂养，即使与其他压力源的持续，产生迅速恢复的Ts，T，和IGF-I。高能量摄入组2减弱了亚临床甲状腺功能减退症和高胆固醇血症，而一致的黄体生成素抑制表明中枢介导的性激素抑制的阈值效应。我们的结论是，低T，TS和IGF-I仍然是可靠的标记急性能源赤字在其他压力的存在下，胆固醇和皮质醇升高提供了有关慢性状态的信息，对应于减少体内脂肪储存。
We tested the hypothesis that key endocrine responses to semistarvation would be attenuated by changing only the food intake in a multistressor environment that also included sustained workload, inadequate sleep, and thermal strain. Serum hormones were compared within and between two groups of healthy young male volunteers participating in the 8-wk US Army Ranger course, with four repeated cycles of restricted energy intakes and refeeding: group I (n = 49) and group 2 (n = 48); energy deficits averaged 1,200 and 1,000 kcal/day, respectively. After 8 wk, most of group I achieved a minimum body fat, serum 3,5,3'-triiodothyronine (T-3) was below normal (78 +/- 20 ng/dl), testosterone (T) approached castrate levels (4.5 +/- 3.9 nmol/l), insulin-like growth factor I(IGF-I) declined by one-half(75 +/- 25 mu g/l), and cholesterol rose from 158 +/- 31 to 217 +/- 39 mg/dl. Bioavailable T3 and T were further reduced by increases in their specific binding proteins in response to declining insulin. Refeeding, even with continuation of the other stressors, produced prompt recovery of Ts, T, and IGF-I. Higher energy intakes ingroup 2 attenuated the subclinical hypothyroidism and hypercholesterolemia, whereas consistent luteinizing hormone suppression indicated centrally mediated threshold effects on gonadal hormone suppression. We conclude that low T, TS, and IGF-I remained reliable markers of acute energy deficits in the presence of other stressors; elevated cholesterol and cortisol provided information about chronic status, corresponding to diminishing body fat stores.