Pancreatic amylase secretion and cytoplasmic free calcium. Effects of ionomycin, phorbol dibutyrate and diacylglycerols alone and in combination.
Pancreatic amylase secretion and cytoplasmic free calcium. Effects of ionomycin, phorbol dibutyrate and diacylglycerols alone and in combination.
复制标题
胰淀粉酶分泌和细胞质游离钙。
DOI：
10.1042/bj2300151
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Rubin,RP
中科院分区：
文献类型：
--
作者：
Merritt,JE;Rubin,RP
蛋白激酶C和Ca2+可能协同作用，激活分泌。本研究考察了离子霉素和二丁酸佛波酯对胰腺腺泡细胞的作用，它们选择性地刺激这两种途径中的一种；它们的刺激作用与受体激动剂（如激活磷脂酶c的碳二醇和小蛋白）的刺激作用进行了比较。Ca2+离子载体离子霉素产生了淀粉酶分泌和细胞内游离Ca2+的剂量依赖性增加（通过quin-2测量）。淀粉酶分泌的增加是由碳乙醇或小蛋白引起的，伴随着细胞内游离Ca2+的持续小幅增加，在最初的峰值之后。然而，在一定水平的淀粉酶分泌下，这些受体激动剂产生的细胞内游离Ca2+的升高比用离子霉素观察到的要小。二丁酸佛蓬通过一种独立于细胞外Ca2+的机制刺激淀粉酶分泌，而细胞内游离Ca2+没有变化。观察了二丁酸佛博尔酯与离子霉素的协同刺激作用，无论佛博尔酯是在离子霉素之前存在还是与离子霉素联合使用。含有不饱和脂肪酸（1,2-二油基甘油和1,3-二油基甘油）的二酰基甘油也能刺激淀粉酶的分泌，并与离子霉素表现出协同作用。这些发现表明，胰腺淀粉酶分泌的完全激活需要刺激Ca2+依赖性和蛋白激酶c激活途径。
Both protein kinase C and Ca2+ may act in concert to bring about activation of secretion. This study examined the actions on pancreatic acini of ionomycin and phorbol dibutyrate, which selectively stimulate one or the other of these pathways; their stimulatory effects were compared with those of receptor agonists, such as carbachol and caerulein, which activate phospholipase C. The Ca2+ ionophore ionomycin produced a dose-dependent increase in amylase secretion and intracellular free Ca2+ (as measured by quin-2). The increase in amylase secretion elicited by carbachol or caerulein was accompanied by a small sustained increase in intracellular free Ca2+, following an initial peak. However, the elevation in intracellular free Ca2+ produced by these receptor agonists for a given level of amylase secretion was less than that observed with ionomycin. Phorbol dibutyrate stimulated amylase secretion by a mechanism that was independent of extracellular Ca2+, and no change in intracellular free Ca2+ was observed. Synergistic stimulatory effects of phorbol dibutyrate and ionomycin were observed, whether the phorbol ester was present before, or in combination with, ionomycin. Diacylglycerols containing unsaturated fatty acids (1,2-dioleoylglycerol and 1,3-dioleoylglycerol) also stimulated amylase secretion and exhibited synergistic effects on secretion with ionomycin. These findings suggest that complete activation of amylase secretion from the pancreas requires stimulation of both Ca2+-dependent and protein kinase C-activated pathways.