Lys-γ3-Melanotropin Binds with High Affinity to the Rat Adrenal Cortex*
Lys-γ3-Melanotropin Binds with High Affinity to the Rat Adrenal Cortex*
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Lys-γ3-促黑激素与大鼠肾上腺皮质具有高亲和力结合*
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
A. Brownie
中科院分区：
文献类型：
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作者：
R. Pedersen;A. Brownie
来自大鼠肾上腺内部区域的部分纯化的质膜制剂对前 γMSH 肽（合成大鼠 Lys-[125I-iodo-Tyr1;]γ3MSH）表现出特异性和高亲和力，即时间和温度依赖性、可逆且可饱和。对去髓肾上腺的研究表明，这种结合至少有一部分是与肾上腺皮质结合的。 Scatchard 分析揭示了放射性配体的一类结合位点（101 fmol/mg 膜蛋白），表观 Kd 为 0.74 nM。然而，这可能低估了受体对天然 pro-γMSH 的亲和力，因为 Lys-γ3MSH 的结合能力在某种程度上因碘化而受损。 Lys-[125I-iodo-Tyr1]γ3MSH 对结合位点的亲和力比 ACTH-(l–24) 高 100 倍，但与 ACTH 不同，Lys-γ3MSH 浓度高达 10 μM 无法刺激膜相关腺苷酸环化酶活性。该亚细胞部分中的鸟苷酸环化酶也对 Lys-γ3 MSH 无反应。用粗膜部分获得的结果...
Partially purified plasma membrane preparations from the inner zones of the rat adrenal exhibit a specific and high affinity for a pro-γMSH peptide, synthetic rat Lys- [125I-iodo-Tyr1;]γ3MSH, that is time and temperature dependent, reversible, and saturable. Studies with demedullated adrenals indicate that at least part of this binding is to the adrenal cortex. Scatchard analysis reveals a single class of binding sites (101 fmol/mg membrane protein) for the radioactive ligand, with an apparent Kd of 0.74 nM. However, this may understate the receptor affinity for native pro-γMSH(s), because the binding capacity of Lys-γ3MSH is impaired somewhat by iodination. Lys-[125I-iodo-Tyr1]γ3MSH exhibits a 100-fold higher affinity for the binding site than ACTH-(l–24), but unlike ACTH, concentrations of Lys-γ3MSH up to 10 μM fail to stimulate membrane-associated adenylate yclase activity. Guanylate cyclase in this subcellular fraction also is unresponsive to Lys-γ3 MSH. Results obtained with crude membrane fractions ...