Jordan D, Veisseire M, Borson-Chazot F, Mornex R
Faculté de Médecine Alexis-Carrel, INSERUM U-197, Lyon, France.
Horm Res. 1987;27(4):216-24. doi: 10.1159/000180823.
We previously observed that under a 12-hour light/12-hour dark schedule (lights off at 19.00 h), adult male Sprague-Dawley rats showed a circadian rhythm for serum thyroid-stimulating hormone (TSH) with a zenith near midday. In the present work, the ontogenesis of serum TSH rhythm was determined as well as pituitary TSH variations. In addition, hypothalamic and blood TRH were measured in these rats aged 15, 25, 40 and 70 days when sacrificed. As from the first age studied (15 days), a hypothalamic thyrotropin-releasing hormone (TRH) circadian rhythm was present. The mesor and the amplitude of this hypothalamic TRH rhythm increased while the rats were growing up, in contrast with the decrease observed for these parameters as far as blood TRH circadian rhythm is concerned. The time of the acrophase moved from 17.32 h in the 15-day-old rats to 13.57 h in the 70-day-old rats, being constantly in phase opposition with the blood TRH acrophase. The low amplitude pituitary TSH circadian rhythm detected in the young rat disappeared in the adult while, in contrast, the serum TSH rhythm became consistent to reach the well-characterized circadian midday peak in the 70-day-old rats.
我们之前观察到，在12小时光照/12小时黑暗的时间表（19:00关灯）下，成年雄性Sprague-Dawley大鼠血清促甲状腺激素（TSH）呈现昼夜节律，峰值接近中午。在本研究中，我们确定了血清TSH节律的个体发生以及垂体TSH的变化。此外，在处死15、25、40和70日龄的这些大鼠时，测量了下丘脑和血液中的促甲状腺激素释放激素（TRH）。从研究的第一个年龄阶段（15天）开始，下丘脑促甲状腺激素释放激素（TRH）就存在昼夜节律。随着大鼠的成长，这种下丘脑TRH节律的中值和幅度增加，而对于血液TRH昼夜节律而言，这些参数则呈现下降趋势。高峰期时间从15日龄大鼠的17.32小时移至70日龄大鼠的13.57小时，始终与血液TRH高峰期呈相位相反。在幼鼠中检测到的低幅度垂体TSH昼夜节律在成年后消失，相反，血清TSH节律变得一致，并在70日龄大鼠中达到特征明显的昼夜中午峰值。
