Kuhl H, Taubert H D
Acta Endocrinol (Copenh). 1975 Apr;78(4):649-63. doi: 10.1530/acta.0.0780649.
The effect of the intravenous administration of several hormones on L-cystine arylamidase in the hypothalamus of the rat was examined. The injection of 10 mug LH into adult male and female rats was followed within 90 min by an increase of the enzyme activity by 50%, while infantile animals were not affected. When prepuberal rats were pretreated sc with testosterone and progesterone. The iv injection of 0.1 mug oestradiol-17beta into female, and of 0.5 mug testosterone into male intact mature rats also resulted in an increase of hypothalamic enzyme activity. The maximal increase in enzyme activity was seen 16 h after steroid treatment. As it had previously been shown that L-cystine arylamidase inactivates LH-RH, it may be assumed that this enzyme is involved in the short-loop feedback of LH. This assumption is based on the observation that an elevation of plasma LH brings about an activation of the enzyme system, which subsequently leads to an increased inactivation of LH-RH in the hypothalamus. This mechanism seems to depend on the presence of certain plasma levels of oestrogen in female, and of testosterone in male animals.
研究了几种激素静脉注射对大鼠下丘脑L-胱氨酸芳基酰胺酶的影响。向成年雄性和雌性大鼠静脉注射10微克促黄体激素（LH）后，90分钟内酶活性增加了50%，而幼年动物则未受影响。当对青春期前大鼠皮下注射睾酮和孕酮进行预处理后，向雌性完整成熟大鼠静脉注射0.1微克17β-雌二醇，向雄性完整成熟大鼠静脉注射0.5微克睾酮，也会导致下丘脑酶活性增加。在类固醇处理后16小时观察到酶活性的最大增加。由于先前已表明L-胱氨酸芳基酰胺酶会使促性腺激素释放激素（LH-RH）失活，因此可以假定该酶参与了LH的短反馈回路。这一假设基于以下观察结果：血浆LH升高会导致酶系统激活，随后导致下丘脑LH-RH失活增加。这种机制似乎取决于雌性动物体内一定水平的雌激素和雄性动物体内一定水平的睾酮的存在。
