Smith A I, Tetaz T, Roberts J L, Glucksman M, Clarke I J, Lew R A
Peptide Biology Laboratory, Baker Medical Research Institute, Prahran, Victoria, Australia.
Biochimie. 1994;76(3-4):288-94. doi: 10.1016/0300-9084(94)90160-0.
In the present studies, we characterized the degradation of gonadotropin-releasing hormone (GnRH) by tissues of the ovine hypothalamo-pituitary axis. Membrane and soluble fractions of the medial basal hypothalamus, the pre-optic area, the median eminence and the anterior pituitary demonstrated greater GnRH-degrading activity than either hypophysial-portal or jugular plasma. The primary stable product of the membrane fractions was GnRH1-3, while the major product of the soluble fractions was GnRH1-5, both fragments were generated by plasma. Of all tissue fractions, the highest specific activity was observed in the soluble median eminence. Partial purification and characterization of soluble hypothalamic peptidase activity suggested that GnRH degradation by this tissue occurs via a two-step mechanism involving both post-proline cleaving enzyme and the metalloendopeptidase 3.4.24.15.
在本研究中，我们对绵羊下丘脑 - 垂体轴组织中促性腺激素释放激素（GnRH）的降解进行了表征。内侧基底部下丘脑、视前区、正中隆起和垂体前叶的膜和可溶性部分表现出比垂体门脉或颈静脉血浆更高的GnRH降解活性。膜部分的主要稳定产物是GnRH1 - 3，而可溶性部分的主要产物是GnRH1 - 5，这两种片段均由血浆产生。在所有组织部分中，可溶性正中隆起的比活性最高。可溶性下丘脑肽酶活性的部分纯化和表征表明，该组织对GnRH的降解通过两步机制进行，涉及脯氨酸后切割酶和金属内肽酶3.4.24.15。
