Murray S S, Burton D W, Deftos L J
Department of Medicine, University of California, La Jolla.
J Bone Miner Res. 1988 Aug;3(4):447-52. doi: 10.1002/jbmr.5650030412.
We have studied the regulation of the secretion and cytoplasmic RNA levels of calcitonin (CT) and Chromogranin-A (CgA) to determine if the biosynthesis and secretion of these two substances are controlled in a coordinated fashion. The studies were conducted in two cell lines, a medullary thyroid carcinoma (MTC) cell line and a lung tumor (BEN) cell line. Both cell types secrete CT and CgA. Forskolin treatment resulted in a significant increase in the secretion of CT and CgA in each cell line and in CT-specific cytoplasmic RNA in the MTC cell line. Treatment with calcium ionophore A23187 resulted in significantly increased secretion of both substances in the lung tumor cells but not in the medullary thyroid carcinoma cells. A significant increase in CT-specific or CgA-specific cytoplasmic RNA was not seen in either cell line. We conclude that the secretion of CT and CgA are regulated in a coordinated fashion in these cell lines through processes that are calcium-mediated and processes that involve cyclic AMP-dependent protein kinase A. However, each of these regulatory pathways is not always operative in a given tissue. The coordinate regulation of the secretion of CT and CgA supports the hypothesis that CgA participates in the secretory process of its associated hormones.
我们研究了降钙素（CT）和嗜铬粒蛋白A（CgA）的分泌及细胞质RNA水平的调节，以确定这两种物质的生物合成和分泌是否以协调的方式受到控制。研究在两种细胞系中进行，一种是甲状腺髓样癌（MTC）细胞系，另一种是肺肿瘤（BEN）细胞系。两种细胞类型均分泌CT和CgA。福司可林处理导致每个细胞系中CT和CgA的分泌以及MTC细胞系中CT特异性细胞质RNA显著增加。用钙离子载体A23187处理导致肺肿瘤细胞中两种物质的分泌显著增加，但在甲状腺髓样癌细胞中未增加。在任一细胞系中均未观察到CT特异性或CgA特异性细胞质RNA的显著增加。我们得出结论，在这些细胞系中，CT和CgA的分泌通过钙介导的过程和涉及环磷酸腺苷依赖性蛋白激酶A的过程以协调的方式受到调节。然而，这些调节途径中的每一种在给定组织中并不总是起作用。CT和CgA分泌的协调调节支持了CgA参与其相关激素分泌过程的假说。
