Neary J T, Kieffer J D, Nakamura C, Mover H, Soodak M, Maloof F
Endocrinology. 1978 Nov;103(5):1849-54. doi: 10.1210/endo-103-5-1849.
The developmental pattern of TRH-degrading activity in rat plasma was determined by measuring the ability of plasma from rats of various ages to degrade TRH into degradation products. From a rate of 0.519 pmol TRH degraded/microliter-1.h-1 on day 8, plasma TRH-degrading activity increased to 18.1 pmol TRH by day 90 in female rats. The increase in rate of formation of proline, a major plasma degradation product, was in very good agreement with the increase in rate of TRH degradation. The major increase in TRH-degrading activity occurred between the third and seventh week of life. A similar pattern of development was observed in male rats; the only significant difference was that plasma from day 90 male rats was approximately 30% more active than that from female rats (P less than 0.002). Daily T3 administration to rats from days 8--26 resulted in a 2-fold increase in plasma TRH-degrading activity (P less than 0.05). The contribution of plasma degradation to the physiological control of TRH activity is not clear, but the magnitude of the increase in plasma TRH-degrading activity (approximately 30-fold) during the maturation of the rat is suggestive of a mechanism of biological significance.
通过测量不同年龄大鼠血浆将促甲状腺激素释放激素（TRH）降解为降解产物的能力，确定了大鼠血浆中TRH降解活性的发育模式。在雌性大鼠中，血浆TRH降解活性从第8天的0.519 pmol TRH降解/微升-1·小时-1增加到第90天的18.1 pmol TRH。主要血浆降解产物脯氨酸形成速率的增加与TRH降解速率的增加非常一致。TRH降解活性的主要增加发生在出生后第三至第七周。在雄性大鼠中观察到类似的发育模式；唯一显著的差异是，90天大的雄性大鼠血浆的活性比雌性大鼠血浆高约30%（P<0.002）。在第8至26天每天给大鼠注射T3导致血浆TRH降解活性增加两倍（P<0.05）。血浆降解对TRH活性生理控制的贡献尚不清楚，但在大鼠成熟过程中血浆TRH降解活性增加的幅度（约30倍）提示了一种具有生物学意义的机制。
