促甲状腺激素释放激素对幼龄和成年大鼠血浆促甲状腺激素水平影响的比较。

Comparison of the effect of TRH on plasma TSH level in young and adult rats.

作者信息

Macho L, Strbák V

出版信息

Endocrinol Exp. 1979 Sep;13(3):139-44.

Abstract

Since it is known that TRH degrading system in plasma is inactive during suckling period in the rat, it was of interest to see whether this might prolong the effect of TRH on plasma TSH. Time course of plasma TSH after s. c. administration of 2 ng TRH g-1 was studied in 7, 48 and 120 day-old rats. The highest basal TSH level (448 +/- 72 microU ml-1) was found in 48 day-old males, while it was the lowest (82 +/- 22.8 microU ml-1) in 7 day-old animals. Time course was essentially the same in all three age groups. If the increase of plasma TSH was compared to the level of saline treated controls at the same time, 8.2 and 10.1 fold increase was found 10 and 30 min after TRH injection, respectively, in 7 day-old pups. However, the increase was only 2.3 and 3.4 fold in older animals at the same time intervals. The highest absolute level obtained during TRH stimulation was found in 48 day-old animals (1055 +/- 121.6 microU ml-1). These results show that the effect of TRH on plasma TSH was not prolonged in neonatal rats thus suggesting that extravascular TRH degradation may be of some importance in TSH regulation.

摘要

由于已知大鼠哺乳期血浆中的促甲状腺激素释放激素（TRH）降解系统无活性，因此研究这是否可能延长TRH对血浆促甲状腺激素（TSH）的作用就很有意义。对7日龄、48日龄和120日龄的大鼠皮下注射2 ng TRH/g后，研究了血浆TSH的时间进程。在48日龄雄性大鼠中发现基础TSH水平最高（448±72 μU/ml），而在7日龄动物中最低（82±22.8 μU/ml）。在所有三个年龄组中，时间进程基本相同。如果将血浆TSH的增加与同时接受生理盐水处理的对照组水平进行比较，在7日龄幼崽中，TRH注射后10分钟和30分钟分别发现增加了8.2倍和10.1倍。然而，在相同时间间隔下，老年动物的增加仅为2.3倍和3.4倍。在TRH刺激期间获得的最高绝对水平出现在48日龄动物中（1055±121.6 μU/ml）。这些结果表明，TRH对新生大鼠血浆TSH的作用并未延长，因此表明血管外TRH降解在TSH调节中可能具有一定重要性。