PITUITARY HORMONES IN NORMAL AND NEOPLASTIC GROWTH

该项目的总体目标是阐明 参与调节生长和功能的机制 肾上腺皮质细胞 在过去的一年里，我们成功地第一次 检测和表征生理相关受体的时间 促肾上腺皮质激素对大鼠肾上腺皮质细胞的影响。 我们还准备了一个 这种激素的光反应性衍生物，并用它来 鉴定肾上腺皮质细胞上的ACTH受体。 此外该 利用光反应性肽鉴定相互作用位点 促肾上腺皮质激素和血清白蛋白之间，这可能是生理上重要的， 激素在孵化过程中的运输。 采用直接免疫荧光法研究了钙在促肾上腺皮质激素（ACTH）作用中的作用。 结合研究和光亲和标记。 结果清楚地 证明钙是必不可少的结合ACTH， 受体和受体的持续占用。 细胞外 钙不是激活类固醇生成所必需的， 与受体结合并通过共价键维持在受体上 附件. 人肾上腺皮质细胞的ACTH受体也是 表征了 具有表观K值的单一类结合位点D 的 1.6± 0.14 nM，发现结合容量为3560个位点/细胞。 cAMP和皮质醇产生的浓度-反应曲线发生偏移 左侧，ACTH浓度为半最大 刺激分别是20- 1和800倍， 约束力 （丙）

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)