Sawin C T, Hershman J M
J Clin Endocrinol Metab. 1976 May;42(5):809-16. doi: 10.1210/jcem-42-5-809.
The response of serum TSH to duplicate tests with each of two doses of TRH (30 mug and 500 mug) was studied in 22 normal young adult men. The mean intra-individual variability of the response assessed by duplicate testing (coefficient of variation) was 17% but was as high as 63% in individual subjects. While the actual range of peak TSH values after 500 mug TRH was 2.7-19.5 muU/ml, those subjects (3 of 22) with a peak TSH value between 2 and 5 muU/ml on one occasion were all greater than 5 muU/ml on another. Thus, despite the intra-individual variability, a peak TSH value after 500 mug TRH of less than 2 muU/ml indicates TSH deficiency and greater than 5 muU/ml indicates normal TSH reserve. A peak value of 2-5 muU/ml is an indication for retesting;; a peak TSH value greater than 5 muU/ml on retesting indicates normal TSH reserve. The use of the maximal increase in TSH above basal values (max deltaTSH) did not have a clear advantage over the use of the peak TSH value although a max deltaTSH greater than 4 muU/ml was equivalent to a peak value greater than 5 muU/ml. No information was lost by using only the TSH value at 30 min after TRH instead of multiple samples. In using these values differences in assay technique should be considered; for example, the use of human TSH standard MRC 68/38 instead of human TSH standard A (MRC 63/14) causes a fall of about 1/3 in measured serum values. The overall TSH response to 500 mug TRH was statistically greater than the response to 30 mug TRH (P less than 0.01); however, in 10 of 22 subjects the response to the two doses was about the same, suggesting that the dose response of TSH to TRH, between 30 mug and 500 mug TRH, is quite shallow. The TSH value 60 min after 500 mug TRH was within 2 muU/ml of the peak TSH value in 12 of 22 subjects on at least one occasion; this pattern of a delayed fall is a normal variant. The peak TSH response to TRH correlated well with the basal level of TSH (P less than 0.001) and thus can be considered a magnifier of the basal level of TSH in normal subjects. While the peak TSH value did not correlate with the basal level of T3, there was a moderate negative correlation of the peak TSH value with the basal level of T4 (P less than 0.02), suggesting that the concentration of serum T4 within the normal range is a determinant of TSH secretion.
对22名正常年轻成年男性研究了血清促甲状腺激素（TSH）对两种剂量促甲状腺激素释放激素（TRH）（30微克和500微克）重复检测的反应。通过重复检测评估的反应的个体内平均变异性（变异系数）为17%，但个别受试者高达63%。虽然500微克TRH后促甲状腺激素峰值的实际范围是2.7 - 19.5微单位/毫升，但那些在某一时刻促甲状腺激素峰值在2至5微单位/毫升之间的受试者（22名中有3名）在另一时刻均大于5微单位/毫升。因此，尽管存在个体内变异性，但500微克TRH后促甲状腺激素峰值小于2微单位/毫升表明促甲状腺激素缺乏，大于5微单位/毫升表明促甲状腺激素储备正常。2至5微单位/毫升的峰值是再次检测的指征；再次检测时促甲状腺激素峰值大于5微单位/毫升表明促甲状腺激素储备正常。使用促甲状腺激素高于基础值的最大增加值（最大△TSH）相对于使用促甲状腺激素峰值并没有明显优势，尽管最大△TSH大于4微单位/毫升相当于峰值大于5微单位/毫升。仅使用TRH后30分钟的促甲状腺激素值而非多个样本不会丢失信息。在使用这些值时应考虑检测技术的差异；例如，使用人促甲状腺激素标准品MRC 68/38而非人促甲状腺激素标准品A（MRC 63/14）会使测得的血清值下降约1/3。总体而言，500微克TRH后的促甲状腺激素反应在统计学上大于30微克TRH后的反应（P小于0.01）；然而，22名受试者中有10名对两种剂量的反应大致相同，这表明在30微克至500微克TRH之间促甲状腺激素对TRH的剂量反应相当平缓。在至少一次检测中，22名受试者中有12名在500微克TRH后60分钟时的促甲状腺激素值在促甲状腺激素峰值的2微单位/毫升范围内；这种延迟下降的模式是一种正常变异。促甲状腺激素对TRH的峰值反应与促甲状腺激素的基础水平密切相关（P小于0.001），因此可被视为正常受试者促甲状腺激素基础水平的放大器。虽然促甲状腺激素峰值与T3的基础水平无关，但促甲状腺激素峰值与T4的基础水平存在中度负相关（P小于0.02），这表明正常范围内血清T4的浓度是促甲状腺激素分泌的一个决定因素。
