Hazum E
Mol Cell Endocrinol. 1982 Apr;26(1-2):217-22. doi: 10.1016/0303-7207(82)90018-1.
The interaction of 125I-labeled gonadotropin releasing hormone (GnRH) agonist, [D-Ser-(t-Bu)6,des-Gly10-ethylamide]-GnRH, and antagonist [D-pGlu1,D-Phe2,D-Trp3,6]-GnRH with rat pituitary membranes was studied. Their binding was affected differently by pretreatment of membranes with neuraminidase and by wheat-germ agglutinin. Pretreatment of the membranes with neuraminidase abolished the specific binding of both antagonist and agonist, in a dose-response manner, with the former being less affected. Wheat-germ agglutinin affected antagonist binding slightly (22% inhibition at 40 microgram/ml) but inhibited agonist binding more markedly (50% at 40 microgram/ml). This inhibitory effect was specific since it was readily reversed by N-acetylglucosamine. Other lectins, such as concanavalin A and soybean agglutinin affected the binding of both agonist and antagonist to only a small degree. These results suggest that the GnRH-receptor of rat pituitary is a glycoprotein which contains sialic acid residue and that GnRH agonists and antagonists bind differently to the same receptor.
研究了125I标记的促性腺激素释放激素（GnRH）激动剂[D-丝氨酸（叔丁基）6，去甘氨酸10-乙酰胺]-GnRH和拮抗剂[D-焦谷氨酸1，D-苯丙氨酸2，D-色氨酸3，6]-GnRH与大鼠垂体膜的相互作用。用神经氨酸酶预处理膜以及用麦胚凝集素处理对它们的结合有不同的影响。用神经氨酸酶预处理膜以剂量反应方式消除了拮抗剂和激动剂的特异性结合，前者受影响较小。麦胚凝集素对拮抗剂结合影响轻微（40微克/毫升时抑制22%），但对激动剂结合抑制更明显（40微克/毫升时抑制50%）。这种抑制作用是特异性的，因为它很容易被N-乙酰葡糖胺逆转。其他凝集素，如伴刀豆球蛋白A和大豆凝集素对激动剂和拮抗剂结合的影响仅很小程度。这些结果表明大鼠垂体的GnRH受体是一种含有唾液酸残基的糖蛋白，并且GnRH激动剂和拮抗剂与同一受体的结合方式不同。
