Calcium-independent and calcium-dependent mechanisms regulate corticotropin-releasing factor-stimulated proopiomelanocortin peptide secretion and messenger ribonucleic acid production.
Calcium-independent and calcium-dependent mechanisms regulate corticotropin-releasing factor-stimulated proopiomelanocortin peptide secretion and messenger ribonucleic acid production.
复制标题
钙非依赖性和钙依赖性机制调节促肾上腺皮质激素释放因子刺激的阿黑皮素原肽分泌和信使核糖核酸产生。
作者：
J. Dave;L. Eiden;D. Lozovsky;J. Waschek;R. Eskay
我们已经评估了基础和促分泌素刺激释放β-内啡肽和PRL和原代培养大鼠垂体前叶细胞中各自的mRNA水平的钙的作用。用钙通道阻滞剂甲氧基维拉帕米（D 600; 10 μ M）或无钙培养基处理垂体前叶细胞1小时，并没有改变β-内啡肽的基础释放，只有部分阻断CRF（10 nM）刺激的β-内啡肽释放。与D 600或无钙培养基对促肾上腺皮质激素细胞的这些作用相反，这两种测试条件均使催乳素细胞的PRL基础分泌减少50-70%，并完全阻断毛喉素（10 μ M）刺激的PRL分泌。虽然从培养基中省略钙导致阿黑皮素原（POMC）和PRL mRNA的基础水平降低50%，但用D 600处理细胞并没有显著改变POMC或PRL mRNA的基础水平。用D 600处理细胞部分阻断CRF刺激的POMC mRNA升高和毛喉素刺激的PRL mRNA升高。钙激动剂钡（1 mM）使β-内啡肽和PRL释放增加2倍，这被D 600阻断。用钡处理细胞对POMC mRNA水平没有影响，但增加PRL mRNA水平。D 600处理的细胞部分阻断钡刺激的PRL mRNA水平。这些发现表明，CRF刺激的β-内啡肽分泌和CRF刺激的POMC mRNA升高的钙依赖性以及钙非依赖性成分。相反，PRL的分泌和生物合成似乎是完全依赖于钙的过程。
We have evaluated the role of calcium in basal and secretagogue-stimulated release of beta-endorphin and PRL and the levels of their respective mRNAs in primary cultured rat anterior pituitary cells. Treatment of anterior pituitary cells with the calcium channel blocker methoxyverapamil (D600; 10 microM) or with calcium-free medium for 1 h did not alter the basal release of beta-endorphin and only partially blocked CRF (10 nM)-stimulated beta-endorphin release. In contrast to these effects of D600 or calcium-free medium on corticotrophs, both of these test conditions decreased basal secretion of PRL from lactotrophs by 50-70% and completely blocked forskolin (10 microM)-stimulated PRL secretion. Although omission of calcium from the culture medium caused a 50% decrease in basal levels of both proopiomelanocortin (POMC) and PRL mRNA, treatment of cells with D600 did not significantly alter the basal levels of POMC or PRL mRNA. Treatment of cells with D600 partially blocked CRF-stimulated elevation of POMC mRNA and forskolin-stimulated elevation of PRL mRNA. The calcium agonist barium (1 mM) produced a 2-fold increase in both beta-endorphin and PRL release, which was blocked by D600. Treatment of cells with barium had no effect on POMC mRNA levels, but increased PRL mRNA levels. D600 treatment of cells partially blocked barium-stimulated PRL mRNA levels. These findings demonstrate a calcium-dependent as well as a calcium-independent component of CRF-stimulated beta-endorphin secretion and CRF-stimulated POMC mRNA elevation. In contrast, PRL secretion and biosynthesis appear to be totally calcium-dependent processes.
小鼠阿片黑皮质素原的完整氨基酸序列，源自阿片黑皮质素原 cDNA 的核苷酸序列。
DOI：
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发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Uhler,M;Herbert,E
通讯作者：
Herbert,E