Catalano R D, Stuve L, Ramachandran J
J Clin Endocrinol Metab. 1986 Feb;62(2):300-4. doi: 10.1210/jcem-62-2-300.
[125I-Tyr23,Phe2,Nle4]ACTH-(1-38) ([125I]ACTH analog), which is equipotent with ACTH, was used to characterize ACTH receptors in human adrenocortical cells. Adrenals were obtained from brain-dead patients at the time of renal harvest with permission. Binding of [125I]ACTH analog to human adrenocortical cells was highly specific, rapid, reversible, and saturable. Analysis of the inhibition of binding of [125I]ACTH analog by ACTH was compatible with a single class of binding sites with an apparent dissociation constant (Kd) of 1.6 nM and a mean binding capacity of 3560 sites/cell. Concentration-response curves for cAMP and cortisol production were shifted to the left of the binding curve, with ACTH concentrations required for half-maximal stimulation being 20- and 720-fold less, respectively, than those for binding. Extracellular calcium was essential for binding and stimulation of cAMP production. These results indicate that human adrenocortical cells contain a single class of ACTH receptors which are highly similar in affinity, capacity, and calcium requirement to those of rat adrenocortical cells, but differ from the rat receptors in the concentration of ACTH needed for cAMP generation.
[125I-酪氨酰23，苯丙氨酰2，异亮氨酰4]促肾上腺皮质激素-(1 - 38)（[125I]促肾上腺皮质激素类似物）与促肾上腺皮质激素具有同等效力，用于表征人肾上腺皮质细胞中的促肾上腺皮质激素受体。在获得许可的情况下，从脑死亡患者肾脏摘取时获取肾上腺。[125I]促肾上腺皮质激素类似物与人肾上腺皮质细胞的结合具有高度特异性、快速、可逆且可饱和。促肾上腺皮质激素对[125I]促肾上腺皮质激素类似物结合的抑制分析与一类结合位点相符，其表观解离常数（Kd）为1.6 nM，平均结合能力为3560个位点/细胞。环磷酸腺苷（cAMP）和皮质醇产生的浓度 - 反应曲线向左偏移至结合曲线左侧，半最大刺激所需的促肾上腺皮质激素浓度分别比结合所需浓度低20倍和720倍。细胞外钙对于结合和cAMP产生的刺激至关重要。这些结果表明，人肾上腺皮质细胞含有一类促肾上腺皮质激素受体，其在亲和力、容量和钙需求方面与大鼠肾上腺皮质细胞的高度相似，但在产生cAMP所需的促肾上腺皮质激素浓度方面与大鼠受体不同。
