THE ACUTE SECRETORY RESPONSE TO ALTERATIONS IN EXTRACELLULAR CALCIUM-CONCENTRATION AND DOPAMINE IN PERIFUSED BOVINE PARATHYROID CELLS
THE ACUTE SECRETORY RESPONSE TO ALTERATIONS IN EXTRACELLULAR CALCIUM-CONCENTRATION AND DOPAMINE IN PERIFUSED BOVINE PARATHYROID CELLS
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DOI：
10.1210/endo-116-3-1123
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发表时间：
1985-01-01
期刊：
影响因子：
4.8
通讯作者：
BURROWES, M
中科院分区：
文献类型：
--
作者：
BROWN, EM;LEOMBRUNO, R;BURROWES, M
灌注分散牛甲状旁腺细胞被用来检查的快速动力学的分泌反应细胞外钙和多巴胺的变化，并比较了激素分泌的变化，在假定的细胞内介质胞浆钙和cAMP的变化。与细胞外Ca从2.0- 0.75mM的降低相关的激素分泌的增加至少与Ca浓度的变化一样快地发生，这表明刺激分泌的滞后时间为秒或更短的量级。低细胞外Ca对激素分泌的初始激活延迟了30-40秒。在QUIN 2负载和未负载的甲状旁腺细胞中，细胞外Ca浓度从0.75-2.0 nM的随后增加产生激素分泌的快速抑制，其不能在时间上与细胞外Ca的变化分开。在负载QUIN 2的细胞中，与细胞外Ca从2.0- 0.75mM降低相关的细胞溶质Ca浓度的降低发生在半衰期约为15 s.将细胞外Ca从0.75升高至0.2 mM时，细胞质Ca浓度的增加具有约的半衰期。20 s.多巴胺（10-5 M）也产生了一个几乎立即3至4倍的刺激PTH [甲状旁腺激素]释放。虽然激素分泌的增加之前释放的cAMP从灌流细胞，细胞内cAMP增加3.4倍，在平行实验中暴露于多巴胺的10秒内。预孵育灌流细胞与多巴胺降低了随后的分泌反应，低细胞外钙。多巴胺刺激的分泌显着更大的细胞预孵育2.0比那些孵育0.75 mM Ca。显然，灌流牛甲状旁腺细胞响应促分泌素的时间过程中观察到的体内和细胞内钙浓度和细胞内cAMP的时间变化是一致的，这些因素在低钙和多巴胺刺激分泌的介导作用，分别。对低Ca和多巴胺的分泌反应的至少一部分可能来自PTH的共同细胞库。
Perifusion of dispersed bovine parathyroid cells was used to examine the rapid kinetics of the secretory response to alterations in extracellular Ca and to dopamine and compared changes in hormone secretion with alterations in the putative intracellular mediators cytosolic Ca and cAMP. The increase in hormone secretion associated with a reduction in extracellular Ca from 2.0-0.75 mM occurred at least as rapidly as the change in Ca concentration, suggesting that the lag time for the stimulation of secretion was of the order of seconds or less. In cells loaded with the intracellular Ca-sensitive dye QUIN 2, the initial activation of hormone secretion by low extracellular Ca was delayed by 30-40 s. In both QUIN 2-loaded and unloaded parathyroid cells, a subsequent increase in extracellular Ca concentration from 0.75-2.0 nM produced a rapid inhibition of hormone secretion which could not be separated temporally from the changes in extracellular Ca. In QUIN 2-loaded cells, the reduction in cytosolic Ca concentration associated with a decrease in extracellular Ca from 2.0-0.75 mM took place with a half-time of .apprx. 15 s. The increase in cytosolic Ca concentration on raising extracellular Ca from 0.75-0.2 mM had a half-time of .apprx. 20 s. Dopamine (10-5 M) also produced a nearly immediate 3- to 4-fold stimulation of PTH [parathyroid hormone] release. Although the increase in hormone secretion preceded the release of cAMP from perifused cells, intracellular cAMP increased 3.4-fold within 10 s of exposure to dopamine in parallel experiments. Preincubation of perifused cells with dopamine reduced the subsequent secretory response to low extracellular Ca. Dopamine-stimulated secretion was significantly greater in cells preincubated with 2.0 than in those incubated with 0.75 mM Ca. Apparently, perifused bovine parathyroid cells respond to secretagogues with a time course comparable to that observed in vivo and that the temporal changes in cytosolic Ca concentration and cellular cAMP are consistent with a mediatory role for these factors in low Ca- and dopamine-stimulated secretion, respectively. At least a portion of the secretory response to low Ca and dopamine may come from a common cellular pool of PTH.