Griffiths E C, Kelly J A, Klootwijk W, Visser T J
Mol Cell Endocrinol. 1980 Apr;18(1):59-67. doi: 10.1016/0303-7207(80)90007-6.
Specific radioimmunoassays for thyrotrophin-releasing hormone (TRH) and deamido-TRH (TRH-OH) were used to investigate the inactivation of TRH by subcellular fractions from rat hypothalamus. TRH-OH was rapidly formed from TRH by an amidase present only in the supernatant fraction at an optimum pH of 7.38; although TRH was degraded by the particulate fraction, no TRH-OH formation was detected. Of several brain areas investigated, the cortex had the highest rate of TRH-OH production and the pituitary the lowest. Once formed in the supernatant fractions, it was found that TRH-OH was stable and did not undergo further degradation. Formation of TRH-OH from TRH appears to be an important step in the tripeptide's enzymic degradation in the brain, so the combined use of specific radioimmunoassays for TRH and TRH-OH may provide a suitable means for studies of the enzymes involved, since these enzymes may contribute to the mechanisms regulating the secretion and duration of action of TRH.
采用促甲状腺激素释放激素（TRH）和脱氨TRH（TRH-OH）的特异性放射免疫分析法，研究大鼠下丘脑亚细胞组分对TRH的失活作用。TRH-OH由TRH通过仅存在于上清液组分中的一种酰胺酶在最适pH 7.38条件下迅速形成；尽管TRH被微粒体组分降解，但未检测到TRH-OH的形成。在所研究的几个脑区中，皮质产生TRH-OH的速率最高，而垂体最低。发现TRH-OH一旦在上清液组分中形成，就很稳定，不会进一步降解。TRH形成TRH-OH似乎是该三肽在脑中酶促降解的一个重要步骤，因此联合使用TRH和TRH-OH的特异性放射免疫分析法可能为研究相关酶提供一种合适的方法，因为这些酶可能参与调节TRH分泌和作用持续时间的机制。
