Bird I M, Williams B C, Walker S W
Department of Clinical Chemistry, Royal Infirmary, Edinburgh, Scotland, UK.
Mol Cell Endocrinol. 1992 Jan;83(1):29-38. doi: 10.1016/0303-7207(92)90192-9.
The identity of phosphoinositol isomers accumulating on stimulation of primary cultures of bovine adrenocortical zona fasciculata/reticularis cells with angiotensin II (AII), in the presence of Li+, has been established by chromatographic separation on a MonoQ HR5/5 column. The metabolism of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) in a broken cell preparation has also been studied in the absence or presence of added ATP. Our results show that Ins(1,4,5)P3 is formed within 5 s of stimulation of whole cells, but is rapidly converted to Ins(1,3,4)P3 through an Ins(1,3,4,5)P4 intermediate. All the phosphoinositol products accumulating on prolonged (15 min) stimulation of whole cells (Ins1P, Ins4P, Ins(1,3)P2, Ins(1,4)P2, Ins(1,3,4)P3, Ins(1,4,5)P3, Ins(1,3,4,5)P4) can be accounted for by the metabolism of Ins(1,4,5)P3 in broken cells, either through direct dephosphorylation in the absence of added ATP (Ins(1,4)P2, Ins4P) or through dephosphorylation of Ins(1,3,4,5)P4 formed in the presence of added ATP (Ins(1,3,4)P3, Ins(1,3)P2 and Ins1P). Our results provide further evidence to suggest that AII stimulates the rapid and sustained breakdown of phosphatidylinositol 4,5-diphosphate (PtdIns(4,5)P2) to form Ins(1,4,5)P3.
在Li⁺存在的情况下，通过在MonoQ HR5/5柱上进行色谱分离，确定了用血管紧张素II（AII）刺激牛肾上腺皮质束状带/网状带细胞原代培养物时积累的磷酸肌醇异构体的身份。还研究了在添加或不添加ATP的情况下，破碎细胞制剂中肌醇1,4,5 -三磷酸（Ins(1,4,5)P3）的代谢情况。我们的结果表明，Ins(1,4,5)P3在全细胞刺激后5秒内形成，但通过Ins(1,3,4,5)P4中间体迅速转化为Ins(1,3,4)P3。在全细胞长时间（15分钟）刺激后积累的所有磷酸肌醇产物（Ins1P、Ins4P、Ins(1,3)P2、Ins(1,4)P2、Ins(1,3,4)P3、Ins(1,4,5)P3、Ins(1,3,4,5)P4），在破碎细胞中可以通过Ins(1,4,5)P3的代谢来解释，要么是在不添加ATP的情况下直接去磷酸化（Ins(1,4)P2、Ins4P），要么是在添加ATP的情况下形成的Ins(1,3,4,5)P4去磷酸化（Ins(1,3,4)P3、Ins(1,3)P2和Ins1P）。我们的结果提供了进一步的证据，表明AII刺激磷脂酰肌醇4,5 -二磷酸（PtdIns(4,5)P2）迅速且持续地分解形成Ins(1,4,5)P3。
