Caron P J, Nieman L K, Rose S R, Nisula B C
J Clin Endocrinol Metab. 1986 May;62(5):960-4. doi: 10.1210/jcem-62-5-960.
In normal individuals, serum TSH concentrations have a circadian pattern characterized by a nocturnal surge which begins in the late afternoon and reaches its peak after midnight. We assessed the nocturnal surge of TSH in 16 patients with pituitary and/or hypothalamic diseases, 6 of whom were judged to be hypothyroid. To assess the magnitude of the nocturnal surge in individual patients, TSH was measured in 5 serum samples obtained during the normal time of the TSH nadir in the late afternoon and in 5 samples obtained during the normal time of the peak of serum TSH after midnight. A significant nocturnal surge of TSH was defined as a significantly greater mean nighttime TSH level than the mean daytime TSH concentration. The nocturnal TSH surge was absent in the 6 patients with central hypothyroidism, while it was present in the 10 euthyroid patients with central lesions. In 6 hypothyroid patients who did not have pituitary or hypothalamic lesions, the nocturnal TSH surge was intact, indicating that hypothyroidism per se does not account for the deficient nocturnal TSH surge in central hypothyroidism. We conclude that central hypothyroidism is characterized by a deficient nocturnal surge of TSH, and accordingly, we suggest that evaluation of the circadian pattern of TSH may be a useful adjunct in making the diagnosis of hypothyroidism in patients with diseases involving the pituitary or hypothalamus.
在正常个体中，血清促甲状腺激素（TSH）浓度呈现昼夜节律模式，其特点是夜间出现高峰，该高峰始于下午晚些时候，并在午夜后达到峰值。我们评估了16例垂体和/或下丘脑疾病患者的TSH夜间高峰情况，其中6例被判定为甲状腺功能减退。为了评估个体患者夜间高峰的幅度，在下午晚些时候TSH最低点的正常时间采集5份血清样本测定TSH，并在午夜后血清TSH峰值的正常时间采集5份样本。TSH显著的夜间高峰定义为夜间TSH平均水平明显高于白天TSH平均浓度。6例中枢性甲状腺功能减退患者未出现TSH夜间高峰，而10例患有中枢性病变的甲状腺功能正常患者则出现了TSH夜间高峰。在6例无垂体或下丘脑病变的甲状腺功能减退患者中，TSH夜间高峰正常，这表明甲状腺功能减退本身并不能解释中枢性甲状腺功能减退患者夜间TSH高峰不足的情况。我们得出结论，中枢性甲状腺功能减退的特征是TSH夜间高峰不足，因此，我们建议评估TSH的昼夜节律模式可能有助于诊断垂体或下丘脑疾病患者的甲状腺功能减退。
