Regulation of phosphatidate synthesis by secretagogues in parotid acinar cells.
Regulation of phosphatidate synthesis by secretagogues in parotid acinar cells.
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腮腺腺泡细胞中促分泌素对磷脂酸合成的调节。
DOI：
10.1042/bj2040587
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
PutneyJr,JW
中科院分区：
文献类型：
--
作者：
Weiss,SJ;McKinney,JS;PutneyJr,JW
研究了磷脂酸盐在大鼠腮腺腺泡细胞中的代谢，特别是已知的通过动员钙离子起作用的激动剂的作用。当细胞在含有10微米-[32P]PI的培养液中孵育时，磷脂酸盐被迅速标记，接近明显的稳定状态，半衰期约为10微米。20分钟。乙酰甲胆碱引起磷酸盐放射性增加一倍以上，这一作用可被M受体拮抗剂阿托品逆转。这些结果表明，磷酸盐标记迅速接近稳态，在预先标记60分钟的细胞中，激动剂引起的放射性增加可能反映净合成，而不是特定放射性的增加。对乙酰甲胆碱的反应磷酸盐合成迅速，在几秒钟的分辨率内发生，没有可测量的延迟。肾上腺素和P物质也能刺激磷脂酸的合成，但这两种激动剂的作用都不如乙酰甲胆碱。钙离子载体离子霉素不能刺激磷脂酸盐的合成。通过使用一种消除受体调节的钙池的方案，已经证明乙酰甲胆碱诱导的磷脂酸盐的形成既不是钙离子内流的结果，也不是钙离子释放的结果。这些结果表明，磷脂酸盐的合成反应具有与先前提出的作为膜钙门控主要介体的作用相一致的特征。
The metabolism of phosphatidate in rat parotid acinar cells was investigated, particularly with regard to the actions of agonists known to act by mobilizing Ca2+. When cells were incubated in medium containing 10 microM-[32P]Pi, phosphatidate was rapidly labelled, approaching an apparent steady-state with a half-time of approx. 20 min. Methacholine provoked a more than doubling of phosphatidate radioactivity, which was reversed by the muscarinic antagonist atropine. These results suggest that phosphatidate labels to near steady-state rapidly and that in cells prelabelled for 60 min the increase in radioactivity induced by agonists probably reflects net synthesis rather than an increase in specific radioactivity. Phosphatidate synthesis in response to methacholine was rapid and occurred, within the resolution of a few seconds, with no measurable latency. Adrenaline and substance P also stimulated phosphatidate synthesis but both agonists were less efficacious than methacholine. A Ca2+ ionophore, ionomycin, did not provoke phosphatidate synthesis. By using a protocol that eliminates the receptor-regulated Ca2+ pool, it was demonstrated that methacholine-induced phosphatidate formation does not come about as a consequence of Ca2+ influx nor of Ca2+ release. These results indicate that the phosphatidate synthesis response has characteristics compatible with its previously suggested role as a primary mediator of membrane Ca2+-gating.