Wynn P C, Aguilera G, Morell J, Catt K J
Biochem Biophys Res Commun. 1983 Jan 27;110(2):602-8. doi: 10.1016/0006-291x(83)91192-0.
Specific receptors for corticotropin-releasing factor (CRF) were identified in the rat anterior pituitary gland by binding studies with 125I-Tyr-CRF. Binding of the labeled CRF analog to pituitary particles was rapid and temperature-dependent, and reached steady state within 45 min at 22 degrees C. The CRF binding sites were saturable and of high affinity, with dissociation constant (Kd) of 0.76 X 10(-9) M. Pituitary binding of 125I-Tyr-CRF was inhibited by CRF, Tyr-CRF and the active 15-41 fragment of CRF, but not by the inactive 21-41 CRF fragment and unrelated peptides. The binding-inhibition potencies of the CRF peptides were similar to their activities as stimuli of adrenocorticotropic hormone (ACTH) release. The high-affinity CRF sites were markedly reduced in adrenalectomized rats, and this change was reversed by dexamethasone treatment. These data indicate that the high-affinity CRF sites demonstrated in the anterior pituitary are the functional receptors which mediate the stimulatory action of the peptide on ACTH release, and that CRF receptors are down-regulated during increased secretion of the hypothalamic hormone.
通过使用125I-酪氨酸-促肾上腺皮质激素释放因子（CRF）进行结合研究，在大鼠垂体前叶中鉴定出了CRF的特异性受体。标记的CRF类似物与垂体颗粒的结合迅速且依赖温度，在22℃下45分钟内达到稳态。CRF结合位点具有饱和性且亲和力高，解离常数（Kd）为0.76×10^(-9)M。125I-酪氨酸-CRF与垂体的结合受到CRF、酪氨酸-CRF以及CRF的活性15-41片段的抑制，但不受无活性的21-41 CRF片段和无关肽的抑制。CRF肽的结合抑制效力与其作为促肾上腺皮质激素（ACTH）释放刺激物的活性相似。在肾上腺切除的大鼠中，高亲和力的CRF位点明显减少，而这种变化可通过地塞米松治疗逆转。这些数据表明，垂体前叶中显示的高亲和力CRF位点是介导该肽对ACTH释放刺激作用的功能性受体，并且在下丘脑激素分泌增加期间CRF受体下调。
