CHANGES IN THE LEVELS OF INOSITOL PHOSPHATES AFTER AGONIST-DEPENDENT HYDROLYSIS OF MEMBRANE PHOSPHOINOSITIDES
CHANGES IN THE LEVELS OF INOSITOL PHOSPHATES AFTER AGONIST-DEPENDENT HYDROLYSIS OF MEMBRANE PHOSPHOINOSITIDES
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DOI：
10.1042/bj2120473
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发表时间：
1983-01-01
影响因子：
4.1
通讯作者：
IRVINE, RF
中科院分区：
文献类型：
--
作者：
BERRIDGE, MJ;DAWSON, RMC;IRVINE, RF
在[大鼠]脑切片、腮腺碎片和昆虫[丽蝇]唾液腺中研究了磷酸肌醇对激动剂的反应。首先将组织与[3 H]肌醇孵育，[3 H]肌醇掺入磷酸肌醇中。经阴离子交换层析、高分辨阴离子交换层析、高压纸离子电泳和纸层析鉴定，所有组织均含有甘油磷酸肌醇、1-磷酸肌醇、1，4-二磷酸肌醇和1，4，5-三磷酸肌醇。没有证据表明存在肌醇1：2-环磷酸。建立了一种简单的阴离子交换色谱分离肌醇磷酸酯的定量分析方法。刺激没有引起任何组织中甘油磷酸肌醇水平的变化。最突出的变化涉及肌醇1，4-二磷酸，这极大地增加了昆虫唾液腺和腮腺刺激后，分别与5-羟色胺和卡巴胆碱。卡巴胆碱还诱导腮腺中肌醇1，4，5-三磷酸水平大幅增加。用卡巴胆碱刺激脑切片诱导双磷酸和三磷酸适度增加。在研究的所有组织中，肌醇1-磷酸的水平存在显著的激动剂依赖性增加。后者可能来源于肌醇1，4-二磷酸，因为昆虫唾液腺的匀浆除了三磷酸酶外还含有二磷酸酶。这些结果表明，在刺激反应途径中的最早的事件是由磷酸二酯酶水解的聚磷酸肌醇，产生肌醇1，4，5-三磷酸和肌醇1，4-二磷酸，随后水解为肌醇1-磷酸和肌醇。肌醇1：2-环磷酸的缺乏可能表明，在刺激后很短的时间内，磷脂酰肌醇不被其特异性磷酸二酯酶分解代谢，或者释放的任何环状衍生物被肌醇1：2-环磷酸2-磷酸水解酶快速水解。
The formation of inositol phosphates in response to agonists was studied in [rat] brain slices, parotid gland fragments and in the insect [blowfly] salivary gland. The tissues were first incubated with [3H]inositol, which was incorporated into the phosphoinositides. All the tissues contained glycerophosphoinositol, inositol 1-phosphate, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate, which were identified by using anion-exchange and high-resolution anion-exchange chromatography, high-voltage paper ionophoresis and paper chromatography. There was no evidence for the existence of inositol 1:2-cyclic phosphate. A simple anion-exchange chromatographic method was developed for separating these inositol phosphates for quantitative analysis. Stimulation caused no change in the levels of glycerophosphoinositol in any of the tissues. The most prominent change concerned inositol 1,4-bisphosphate, which increased enormously in the insect salivary gland and parotid gland after stimulation with 5-hydroxytryptamine and carbachol, respectively. Carbachol also induced a large increase in the level of inositol 1,4,5-trisphosphate in the parotid. Stimulation of brain slices with carbachol induced modest increase in the bis- and tris-phosphate. In all the tissues studied, there was a significant agonist-dependent increase in the level of inositol 1-phosphate. The latter may be derived from inositol 1,4-bisphosphate, because homogenates of the insect salivary gland contain a bisphosphatase in addition to a trisphosphatase. These results suggest that the earliest event in the stimulus-response pathway is the hydrolysis of polyphosphoinositides by a phosphodiesterase to yield inositol 1,4,5-trisphosphate and inositol 1,4-bisphosphate, which are subsequently hydrolysed to inositol 1-phosphate and inositol. The absence of inositol 1:2-cyclic phosphate could indicate that, at very short times after stimulation, phosphatidylinositol is not catabolized by its specific phosphodiesterase, or that any cyclic derivative liberated is rapidly hydrolysed by inositol 1:2-cyclic phosphate 2-phosphohydrolase.