De Remigis P, Vianale L, Damiani A, D'Angelo M, Sensi S
Chronobiologia. 1982 Apr-Jun;9(2):127-32.
The PRL response to TRH constitutes an important clinical tool for diagnosing forms of hyperprolactinemic syndrome. Hence it is important to establish the characteristics of the circadian variation in the response of PRL to TRH to improve the diagnostic value of the test. Six male subjects, ranging in age from 23 to 24 years, participated in this study. All were considered healthy on the basis of clinical examination, biochemical and hormonal tests. Six TRH tests were performed on each subject, one test every other day during a total span of 12 days. Each test was performed at a different clock hour: 0000, 0400, 0800, 1200, 1600, 2000. For the test, subjects received 200 microgram TRH intravenously. Blood samples were drawn from a catheterized arm vein before the TRH injection (basal value) and 20, 30, 60 and 120 min after injection. At each timepoint 5 endpoints were determined for PRL on each subject. The population mean cosinor, according to Halberg, was used to investigate the circadian rhythm in each of the endpoints. All the 5 endpoints for PRL are consistent on showing p values near 0.5 and acrophase estimates before midnight (while basal value displays acrophase at 0400). Further investigations are necessary to clarify these circadian rhythms and the shift of the acrophases.
催乳素（PRL）对促甲状腺激素释放激素（TRH）的反应是诊断高催乳素血症综合征形式的一项重要临床工具。因此，确定PRL对TRH反应的昼夜变化特征对于提高该检测的诊断价值很重要。6名年龄在23至24岁之间的男性受试者参与了本研究。根据临床检查、生化和激素检测，所有受试者均被认为健康。对每位受试者进行了6次TRH检测，在总共12天的时间里每隔一天进行一次检测。每次检测在不同的时钟时间进行：00:00、04:00、08:00、12:00、16:00、20:00。检测时，受试者静脉注射200微克TRH。在注射TRH前（基础值）以及注射后20、30、60和120分钟，从经导管插入的手臂静脉采集血样。在每个时间点，为每位受试者测定PRL的5个终点值。根据哈尔伯格法计算总体平均余弦法，用于研究每个终点值的昼夜节律。PRL的所有5个终点值的p值均接近0.5，且峰值相位估计在午夜之前（而基础值的峰值相位在04:00）。需要进一步研究以阐明这些昼夜节律和峰值相位的变化。
