Dexamethasone effects on beta-adrenergic receptors and adenylate cyclase regulatory proteins Gs and Gi in ROS 17/2.8 cells.
Dexamethasone effects on beta-adrenergic receptors and adenylate cyclase regulatory proteins Gs and Gi in ROS 17/2.8 cells.
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DOI：
10.1210/endo-118-6-2510
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发表时间：
1986-06
期刊：
影响因子：
4.8
通讯作者：
S. Rodan;G. Rodan
中科院分区：
文献类型：
--
作者：
S. Rodan;G. Rodan
用地塞米松(Dex)处理ROS 17/2.8细胞，可增加(-)异丙肾上腺素(ISO)、甲状旁腺素(PTH)、霍乱毒素、鸟嘌呤核苷酸、NaF-和Forsklin刺激的腺苷环化酶的活性。激素刺激在加入地塞米松后12h开始明显增强。在地塞米松处理的细胞中，可被ISO取代的(-)-[~3H]二氢阿普洛尔结合量增加了2倍。这种作用依赖于蛋白质的合成，并与腺苷环化酶刺激增加的程度和时间进程密切相关。在地塞米松处理的细胞中，5‘-酰亚胺基二磷酸鸟苷刺激的腺苷酸环化酶的最大速度增加，在ISO存在的情况下，鸟氨酰-5’-亚胺二磷酸酶激活的滞后时间从3分钟缩短到1分钟，霍乱毒素对腺苷环化酶的刺激增加，在霍乱毒素存在的情况下，[32P]NAD增加了47000和42000molwt蛋白的标记。[32P]在百日咳毒素存在的情况下，NAD核糖化导致40,000摩尔重量蛋白的标记，在地塞米松处理的细胞中，该蛋白也增加了20-50%。然而，百日咳毒素治疗并没有增加或减少激素刺激的影响，尽管它增加了对甲状旁腺素和(-)ISO的cAMP反应。这些发现表明，地塞米松通过共同增加激素受体的数量和鸟嘌呤核苷酸结合调节蛋白Gs的丰度，增加了(-)ISO对ROS17/2.8细胞腺苷环化酶的刺激。
Treatment of ROS 17/2.8 cells with dexamethasone (dex) increases (-)isoproterenol (ISO)-, PTH-, cholera toxin-, guanine nucleotide-, NaF-, and forskolin-stimulated adenylate cyclase activity. Enhanced hormone stimulation was first apparent 12 h after dex addition. (-)-[3H]Dihydroalprenolol binding, displaceable by ISO, increased up to 2-fold in dex-treated cells. This effect depended on protein synthesis and closely paralleled the extent and time course of the increase in adenylate cyclase stimulation. In dex-treated cells there was also an increase in the maximum velocity of guanyl-5'-yl imidodiphosphate-stimulated adenylate cyclase, a decrease in the lag time for guanyl-5'-yl imidodiphosphate enzyme activation in the presence of ISO from 3 to 1 min, increased stimulation of adenylate cyclase by cholera toxin, and increased labeling of 47,000 and 42,000 mol wt proteins by [32P]NAD in the presence of cholera toxin. [32P]NAD ribosylation in the presence of pertussis toxin resulted in the labeling of 40,000 mol wt protein, which was also increased by 20-50% in dex-treated cells. However, pertussis toxin treatment did not augment or reduce the effect on hormone stimulation, although it increased the cAMP response to PTH and (-)ISO. These findings suggest that dex increases (-)ISO stimulation of adenylate cyclase in ROS 17/2.8 cells by jointly increasing the number of hormone receptors and the abundance of Gs, the guanine nucleotide binding regulatory protein.