Regulation of parathyroid hormone release and cytosolic calcium by extracellular calcium in dispersed and cultured bovine and pathological human parathyroid cells.
Regulation of parathyroid hormone release and cytosolic calcium by extracellular calcium in dispersed and cultured bovine and pathological human parathyroid cells.
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分散培养的牛和病理人甲状旁腺细胞中细胞外钙对甲状旁腺激素释放和胞质钙的调节。
DOI：
10.1172/jci111696
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Marynick,S
中科院分区：
文献类型：
--
作者：
LeBoff,MS;Shoback,D;Brown,EM;Thatcher,J;Leombruno,R;Beaudoin,D;Henry,M;Wilson,R;Pallotta,J;Marynick,S
甲状旁腺对钙敏感性的改变可能导致甲状旁腺功能亢进时PTH分泌过多。由于细胞内钙浓度可能介导细胞外钙对PTH释放的影响，我们采用了钙敏感的细胞内染料QUIN-2检查细胞外钙，细胞内钙，和PTH分泌之间的关系在成人，新生儿，培养牛以及病理性人甲状旁腺细胞。甲状旁腺素释放测定使用C-和N-末端放射免疫分析。新生牛甲状旁腺细胞表现出更大的分泌设定点（Ca++浓度导致甲状旁腺素释放最大抑制的一半）比成人细胞（1.27 +/- 0.11 vs. 1.06 +/- 0.11 mM细胞外钙，P小于0.01），新生牛甲状旁腺细胞胞浆钙浓度升高到一定水平需要比成年牛甲状旁腺细胞稍高的细胞外钙。在个别新生儿和成人细胞制剂，有一个密切的相关性之间的设定点的分泌和“设定点”的胞浆钙（r = 0.832，P小于0.001）。在5个人甲状旁腺腺瘤的细胞中，其具有增加的分泌设定点，细胞外钙浓度升高胞质钙浓度到给定水平所需的细胞外钙浓度略大于新生儿细胞。在四种人甲状旁腺细胞制备物中，分泌设定点与胞浆钙之间存在显著相关性（r = 0.856，P <0.01）。由于新生牛和病理人类甲状旁腺显示细胞增生，我们研究了细胞增殖和培养的牛甲状旁腺细胞中PTH释放和胞浆钙浓度的调节之间的时间关系。通过3 H-胸苷掺入估计的细胞增殖在培养物中显著增加，从第1天（培养的前24小时）的104 +/- 10.1计数/孔分别增加至第2天和第4天的588 +/- 188和6，156 +/- 649计数/孔。在第1天培养的细胞中，高Ca++（2-3 mM）抑制最大PTH释放58.8 +/-3.2%，在第2天和第4天分别显著降低（P <0.001）至38.2 +/- 1.9和17.1 +/- 3.7%。第1天在3 mM钙水平下观察到的细胞溶质钙为701 +/- 43 nM，第2天和第4天分别降至466 +/- 60和314 +/- 14 nM（P <0.05）。在细胞外高钙条件下，PTH释放的最大抑制率与细胞内钙浓度呈显著正相关（r = 0.99，P < 0.001）。因此，在培养细胞的活跃增殖过程中，在给定的细胞外钙浓度下，细胞溶质钙的调节发生改变，并且细胞外钙对PTH释放和细胞溶质钙的调节的变化可能与增强的细胞增殖有关。
Alterations in parathyroid glandular sensitivity to calcium may contribute to the hypersecretion of PTH in hyperparathyroidism. Since the cytosolic calcium concentration may mediate the effects of extracellular calcium on PTH release, we have employed the calcium-sensitive intracellular dye QUIN-2 to examine the relationship between extracellular calcium, cytosolic calcium, and PTH secretion in adult, neonatal, and cultured bovine as well as pathological human parathyroid cells. PTH release was measured using C- and N-terminal radioimmunoassays. Neonatal bovine parathyroid cells showed a greater set-point for secretion (the Ca++ concentration causing half of the maximal inhibition of PTH release) than adult cells (1.27 +/- 0.11 vs. 1.06 +/- 0.11 mM extracellular calcium, P less than 0.01), and a slightly higher extracellular calcium was necessary to raise the cytosolic calcium concentration to a given level in neonatal than in adult bovine parathyroid cells. In individual neonatal and adult cell preparations, there was a close correlation between the set-point for secretion and the "set-point" for cytosolic calcium (r = 0.832, P less than 0.001). In cells from five human parathyroid adenomas, which had an increase in set-point for secretion, the extracellular calcium concentration necessary to raise the cytosolic calcium concentration to a given level was slightly greater than in the neonatal cells. In four preparations of human parathyroid cells there was a significant correlation between the set-points for secretion and cytosolic calcium (r = 0.856, P less than 0.01). Because neonatal bovine and pathological human parathyroid glands show cellular hyperplasia, we studied the temporal relationship between cellular proliferation and the regulation of PTH release and cytosolic calcium concentration in cultured bovine parathyroid cells. Cellular proliferation, estimated by 3H-thymidine incorporation, increased significantly in culture from 104 +/- 10.1 counts/well on day 1 (first 24 h in culture) to 588 +/- 188 and 6,156 +/- 649 counts/well on days 2 and 4, respectively. In cultured cells on day 1, highly Ca++ (2-3 mM) inhibited maximal PTH release by 58.8 +/- 3.2%, which decreased significantly (P less than 0.001) to 38.2 +/- 1.9 and 17.1 +/- 3.7% on days 2 and 4, respectively. The cytosolic calcium observed at 3 mM calcium on day 1 was 701 +/- 43 nM, which declined to 466 +/- 60 and 314 +/- 14 nM on days 2 and 4 (P less than 0.05). There was a close correlation between this progressive decrease in maximal inhibition of PTH release and the cytosolic calcium at high extracellular calcium in cultured cells (r = 0.99, P < 0.001). Thus, during active proliferation of cultured cells, there is an alteration in the regulation of cytosolic calcium at a given extracellular calcium concentration, and changes in the regulation of PTH release and cytosolic calcium by extracellular calcium may be related to enhanced cellular proliferation.