PITUITARY HORMONES IN NORMAL AND NEOPLASTIC GROWTH

这个项目的总体目标是阐明分子 参与调节细胞生长和功能的机制 肾上腺皮质细胞。在过去的一年里，我们第一次取得了成功 检测和表征生理相关受体的时间 对大鼠肾上腺皮质细胞的促肾上腺皮质激素。我们还准备了一份 很好地表征了荷尔蒙的光反应衍生物，并将其用于 鉴定肾上腺皮质细胞上的ACTH受体。此外， 用光反应肽来确定相互作用的位置 ACTH和血清白蛋白之间的关系，这可能是生理上重要的 孵化过程中荷尔蒙的运输。 用直接法研究钙在促肾上腺皮质激素作用中的作用 结合研究和光亲和标记。结果很明显 证明钙是促肾上腺皮质激素与其结合所必需的 对于受体的持续占用和对受体的持续占用。胞外 一旦激素产生，激活类固醇合成就不需要钙 与受体结合，并通过共价维持在受体上 依恋。人肾上腺皮质细胞的ACTH受体也 特色化的。一类具有明显Kd值的结合位点 1.6±0.14 nM，结合容量为3560个/细胞。 CAMP和皮质醇产生的浓度-反应曲线发生了移动 左侧，ACTH浓度需要达到半极量 刺激分别比用药少20倍和800倍 有约束力的。(C)

The overall objective of this project is to elucidate the molecular mechanisms involved in the regulation of the growth and function of adrenocortical cells. During the past year, we succeeded for the first time in detecting and characterizing the physiologically relevant receptors for ACTH on rat adrenocortical cells. We also prepared a well-characterized photoreactive derivative of the hormone and used it to identify the ACTH receptor on adrenocortical cells. In addition, the photoreactive peptide was employed to identify the site of interaction between ACTH and serum albumin, which may be physiologically important in the transport of the hormone in incubation. The role of calcium in the actions of ACTH was investigated by direct binding studies and photoaffinity labeling. The results clearly demonstrate that calcium is essential for the binding of ACTH to its receptor and for continued occupancy of the receptor. Extracellular calcium is not necessary for activation of steroidogenesis once the hormone is bound to the receptor and maintained on the receptor by covalent attachment. ACTH receptors in human adrenocortical cells were also characterized. A single class of binding sites with an apparent KD of 1.6 + 0.14 nM and a binding capacity of 3560 sites/cell was found. Concentration-response curves for cAMP and cortisol production were shifted to the left, with concentrations of ACTH required for half-maximal stimulation being 20-\and 800-fold less, respectively, than that for binding. (C)