Campen C A, Lai M T, Kraft P, Kirchner T, Phillips A, Hahn D W, Rivier J
Department of Reproductive Research, R.W. Johnson Pharmaceutical Research Institute, Raritan, NJ 08869, USA.
Biochem Pharmacol. 1995 May 11;49(9):1313-21. doi: 10.1016/0006-2952(95)00027-w.
We report here the biological characterization of azaline B, a new gonadotropin releasing hormone (GnRH) receptor antagonist, with the following amino acid sequence: [Ac-D-Nal1, D-Cpa2, D-Pal3, Aph5(atz), D-Aph6(atz), Ilys8, D-Ala10]-GnRH. Azaline B was shown to suppress several reproductive processes in rats including ovulation, and had very low anaphylactoid activity compared with other GnRH antagonists. Azaline B inhibited histrelin (a GnRH agonist)-mediated follicle stimulating hormone (FSH) and luteinizing hormone (LH) release from cultured rat pituitary cells. Three antagonists ([Nal-Glu]-GnRH, [Nal-Lys]-GnRH ("antide"), and azaline B) inhibited 0.1 nM histrelin-mediated gonadotropin release to baseline levels with EC50 values of approximately 0.6 nM. Azaline B, when injected s.c. into rats on the afternoon of proestrus, was more potent at inhibiting ovulation than either [Nal-Glu]-GnRH or [Nal-Lys]-GnRH. The relative order of antiovulatory potencies of the three antagonists was azaline B > [Nal-Glu]-GnRH > [Nal-Lys]-GnRH. Similar azaline B potency was shown by its ability to suppress gonadotropin levels in castrated rats. The improved selectivity of azaline B was demonstrated when it was compared with other GnRH antagonists in the cutaneous anaphylactoid assay (local wheal response) in rats. Results with azaline B were not significantly different from results with vehicle in this assay. [Nal-Glu]-GnRH was more than twice as potent as [Nal-Lys]-GnRH in stimulating a wheal response. Furthermore, the maximal wheal response produced by azaline B was only 0.6 times that of [Nal-Lys]-GnRH, currently one of the most selective antagonists identified. Finally, both azaline B and [Nal-Lys]-GnRH were much less potent than [Nal-Glu]-GnRH in the guinea pig cardiopulmonary anaphylactoid assay after i.v. administration. These data show that azaline B is a potent and selective GnRH receptor antagonist with little or no anaphylactoid activity in animal models, and therefore has potential for use in the treatment of many reproductive endocrine disorders, as well as for use as a contraceptive.
我们在此报告氮杂环庚三烯B的生物学特性，它是一种新型促性腺激素释放激素（GnRH）受体拮抗剂，其氨基酸序列如下：[Ac-D-Nal1, D-Cpa2, D-Pal3, Aph5(atz), D-Aph6(atz), Ilys8, D-Ala10]-GnRH。氮杂环庚三烯B已被证明可抑制大鼠的多种生殖过程，包括排卵，并且与其他GnRH拮抗剂相比，其类过敏活性非常低。氮杂环庚三烯B可抑制组胺瑞林（一种GnRH激动剂）介导的大鼠垂体细胞培养物中促卵泡激素（FSH）和促黄体生成素（LH）的释放。三种拮抗剂（[Nal-Glu]-GnRH、[Nal-Lys]-GnRH（“antide”）和氮杂环庚三烯B）可将0.1 nM组胺瑞林介导的促性腺激素释放抑制至基线水平，EC50值约为0.6 nM。在动情前期下午皮下注射氮杂环庚三烯B时，其抑制排卵的效力比[Nal-Glu]-GnRH或[Nal-Lys]-GnRH更强。三种拮抗剂的抗排卵效力相对顺序为氮杂环庚三烯B > [Nal-Glu]-GnRH > [Nal-Lys]-GnRH。氮杂环庚三烯B在抑制去势大鼠促性腺激素水平方面也显示出类似的效力。当在大鼠的皮肤类过敏试验（局部风团反应）中与其他GnRH拮抗剂进行比较时，氮杂环庚三烯B的选择性得到了提高。在该试验中，氮杂环庚三烯B的结果与赋形剂的结果无显著差异。[Nal-Glu]-GnRH在刺激风团反应方面的效力是[Nal-Lys]-GnRH的两倍多。此外，氮杂环庚三烯B产生的最大风团反应仅为[Nal-Lys]-GnRH的0.6倍，[Nal-Lys]-GnRH是目前已鉴定出的最具选择性的拮抗剂之一。最后，在静脉注射后，在豚鼠心肺类过敏试验中，氮杂环庚三烯B和[Nal-Lys]-GnRH的效力均远低于[Nal-Glu]-GnRH。这些数据表明，氮杂环庚三烯B是一种强效且选择性的GnRH受体拮抗剂，在动物模型中几乎没有或没有类过敏活性，因此有潜力用于治疗多种生殖内分泌疾病以及用作避孕药。
