Azhar S, Menon K M
Biochem J. 1981 Oct 15;200(1):153-9. doi: 10.1042/bj2000153.
Pretreatment of ovarian cells with concanavalin A and wheat-germ agglutinin blocked the gonadotropin-induced cyclic AMP and progesterone responses and this effect was time- and concentration-dependent. Basal production of either cyclic AMP or progesterone, however, was not affected by treatment of cells with lectin. The effect of concanavalin A on gonadotropin-mediated cyclic AMP and progesterone responses was blocked by alpha-methyl D-mannoside and alpha-methyl d-glucoside. Similarly the inhibitory effect of wheat-germ agglutinin was reversed by N-acetyl-D-glucosamine. Pretreatment of ovarian cells with concanavalin A or wheat-germ agglutinin had no effect on protein synthesis in the ovary as monitored by [3H]proline incorporation studies. Concanavalin A and wheat-germ agglutinin did not affect steroid production in response to dibutyryl cyclic AMP and 8-bromo cyclic AMP, indicating that the inhibitory action of lectin was occurring at a step before cyclic AMP formation. Lectins specific for L-fucose, D-galactose and N-acetyl-D-galactosamine, gorse seed agglutinin, peanut agglutinin and Dolichos biflorus agglutinin respectively, did not interfere with gonadotropin-induced cyclic AMP and progesterone responses. The present studies suggest that gonadotropin receptors may be glycoprotein in nature or closely associated with glycoprotein structures with the carbohydrate chain containing N-acetyl-D-glucosamine, mannose and possibly N-acetylneuraminic acid.
用伴刀豆球蛋白A和麦胚凝集素对卵巢细胞进行预处理，可阻断促性腺激素诱导的环磷酸腺苷（cAMP）和孕酮反应，且这种作用具有时间和浓度依赖性。然而，用凝集素处理细胞对cAMP或孕酮的基础分泌没有影响。伴刀豆球蛋白A对促性腺激素介导的cAMP和孕酮反应的作用可被α-甲基-D-甘露糖苷和α-甲基-D-葡萄糖苷阻断。同样，N-乙酰-D-葡萄糖胺可逆转麦胚凝集素的抑制作用。通过[3H]脯氨酸掺入研究监测发现，用伴刀豆球蛋白A或麦胚凝集素对卵巢细胞进行预处理对卵巢中的蛋白质合成没有影响。伴刀豆球蛋白A和麦胚凝集素不影响对二丁酰环磷酸腺苷和8-溴环磷酸腺苷的类固醇生成反应，这表明凝集素的抑制作用发生在环磷酸腺苷形成之前的步骤。分别对L-岩藻糖、D-半乳糖和N-乙酰-D-半乳糖胺具有特异性的凝集素，即金雀花种子凝集素、花生凝集素和双花扁豆凝集素，不干扰促性腺激素诱导的cAMP和孕酮反应。目前的研究表明，促性腺激素受体可能本质上是糖蛋白，或者与糖蛋白结构密切相关，其碳水化合物链含有N-乙酰-D-葡萄糖胺、甘露糖以及可能的N-乙酰神经氨酸。
