Pituitary-thyroid hormone economy in healthy aging men: basal indices of thyroid function and thyrotropin responses to constant infusions of thyrotropin releasing hormone.
Pituitary-thyroid hormone economy in healthy aging men: basal indices of thyroid function and thyrotropin responses to constant infusions of thyrotropin releasing hormone.
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健康老年男性的垂体-甲状腺激素经济：甲状腺功能的基础指数和促甲状腺激素对持续输注促甲状腺激素释放激素的反应。
DOI：
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发表时间：
1984
影响因子：
5.8
通讯作者：
M. R. Blackman
中科院分区：
文献类型：
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作者：
S. Harman;R. E. Wehmann;M. R. Blackman
为了评估与甲状腺疾病或甲状腺外疾病不同的衰老对甲状腺功能某些指标的影响，我们研究了74名来自巴尔的摩老龄化纵向研究的健康流动男性。测定每位受试者的基础血清T4、T3、rT3、甲状腺素结合球蛋白（TBG）和T3树脂摄取（T3RU）值，计算游离T4指数（FT4I = T4 X T3RU/100）、游离T3指数（FT3I = T3 X T3RU/100）和T4/TBG比值。我们使用超灵敏的RIA来测量正常范围内TSH基础浓度的变化。然后，我们以恒定速率（0.4微克/分静脉）向其中63名男性注射TRH，持续240分钟；注射过程中每隔15分钟采集血清样本，用常规RIA分析TSH。受试者按年龄分为3组；A (n = 26，平均年龄= 39.4),B (n = 23，平均年龄= 60.0),C （n = 25，平均年龄= 79.6）。采用Duncan多元极差检验和回归分析进行方差分析。血清T4、TBG、T3RU基础值随年龄变化无统计学意义（P > 0.05）。A组与C组比较，血清T3 （-11%, P < 0.05）、FT3I （-13%, P < 0.02）、FT4I （-11%, P < 0.01）、T4/TBG比值（-12%,P < 0.01）、TSH升高（+38%,P < 0.05）。对于这些变量，B组的平均值介于A组和c组的平均值之间，但与A组和c组的平均值没有显著差异。回归分析显示，年龄与T3、FT3I、FT4I、T4/TBG和TSH在P水平上的相关性与邓肯检验的结果相似。没有老年人表现出基线TSH升高（大于7微克/毫升）或T4下降（小于5微克/分升），表明我们的老年组不存在原发性甲状腺功能减退。除FT3I外，C组基础TSH浓度与甲状腺功能指标均无显著相关（r = -0.43, P < 0.05）。在所有年龄组中，TSH对TRH的反应表现出早高峰和晚高峰的双相模式。（摘要删节为400字）
In order to assess the effects of aging, as distinct from those of thyroid disease or extrathyroidal illness, on certain indices of thyroid function, we studied 74 healthy, ambulatory men recruited from the Baltimore Longitudinal Study on Aging. We determined basal serum values of T4, T3, rT3, thyroxine-binding globulin (TBG), and T3 resin uptake (T3RU) and calculated the free T4 index (FT4I = T4 X T3RU/100), free T3 index (FT3I = T3 X T3RU/100), and T4/TBG ratio for each subject. We used an ultrasensitive RIA to measure variations in basal concentrations of TSH within the normal range. We then infused TRH at a constant rate (0.4 microgram/min iv) for 240 min into 63 of the same men; serum samples, collected at 15-min intervals during the infusion, were analyzed for TSH by routine RIA. Subjects were divided into 3 groups according to age; A (n = 26, mean age = 39.4), B (n = 23, mean age = 60.0), and C (n = 25, mean age = 79.6). Analysis of variance with Duncan's multiple range test and regression analysis were used to evaluate data. There was no significant (P greater than 0.05) variation with age of basal serum values of T4, TBG, or T3RU. Comparison of groups A and C showed significant decreases of mean values of serum T3 (-11%, P less than 0.05), FT3I (-13%, P = 0.02), FT4I (-11%, P less than 0.01), and T4/TBG ratio (-12%, P less than 0.01) and an increase in serum TSH (+38%, P less than 0.05). For these variables, the mean values for group B were intermediate between, but not significantly different from, those of A and C. Regression analysis showed significant correlations of age with T3, FT3I, FT4I, T4/TBG, and TSH at P levels similar to those obtained by Duncan's test. No elderly individual exhibited a baseline elevation of TSH (greater than 7 microU/ml) or depression of T4 (less than 5 micrograms/dl), suggesting that primary hypothyroidism was not present in our old group. The basal TSH concentration did not correlate significantly with any index of thyroid function except with FT3I in group C (r = -0.43, P less than 0.05). In all age groups the TSH responses to TRH exhibited a biphasic pattern with early and late peaks.(ABSTRACT TRUNCATED AT 400 WORDS)