Hazum E, Keinan D
Mol Cell Endocrinol. 1984 May;35(2-3):107-11. doi: 10.1016/0303-7207(84)90006-6.
Bovine pituitary gonadotropin-releasing hormone (GnRH) receptors were characterized and identified utilizing a superactive GnRH analog, Buserelin [( D-Ser(t-Bu)6, des-Gly10-ethylamide]-GnRH), and a photoreactive GnRH analog, [azidobenzoyl-D- Lys6 ]-GnRH. Both analogs bind with high affinity to a single class of receptors, with apparent IC50 values of 0.5 nM and 1 nM, respectively. The binding of 125I-labeled Buserelin to pituitary membranes was inhibited, in a dose-responsive manner, by both trypsin and chymotrypsin, with the former being less effective. Neuraminidase at a concentration up to 100 micrograms/ml did not affect the binding. Lectins, such as concanavalin A and wheat-germ agglutinin, at a concentration range of 20-200 micrograms/ml had no effect on the binding, whereas soybean agglutinin at high concentrations (150 and 200 micrograms/ml) slightly inhibited the specific binding. Photoaffinity labeling of the bovine pituitary GnRH receptors resulted in the identification of two specific bands with apparent molecular weights of 60 K and 30 K daltons. The latter probably represents very low affinity binding sites. Both specific bands were sensitive to trypsin and chymotrypsin treatment but were not affected by neuraminidase treatment. These results suggest a slight difference between rat and bovine pituitary GnRH receptors.
利用一种超活性促性腺激素释放激素（GnRH）类似物布舍瑞林[（D-丝氨酸（叔丁基）6，去甘氨酸10-乙酰胺）-GnRH]和一种光反应性GnRH类似物[叠氮苯甲酰-D-赖氨酸6]-GnRH，对牛垂体GnRH受体进行了表征和鉴定。这两种类似物均以高亲和力与单一类别的受体结合，其表观半数抑制浓度（IC50）值分别为0.5纳摩尔和1纳摩尔。125I标记的布舍瑞林与垂体膜的结合受到胰蛋白酶和糜蛋白酶的剂量依赖性抑制，前者的效果较差。浓度高达100微克/毫升的神经氨酸酶不影响结合。刀豆球蛋白A和麦胚凝集素等凝集素在20 - 200微克/毫升的浓度范围内对结合无影响，而高浓度（150和200微克/毫升）的大豆凝集素对特异性结合有轻微抑制作用。牛垂体GnRH受体的光亲和标记鉴定出两条特异性条带，其表观分子量分别为60千道尔顿和30千道尔顿。后者可能代表极低亲和力的结合位点。两条特异性条带对胰蛋白酶和糜蛋白酶处理敏感，但不受神经氨酸酶处理的影响。这些结果表明大鼠和牛垂体GnRH受体之间存在细微差异。
