Litosch I, Lin S H, Fain J N
J Biol Chem. 1983 Nov 25;258(22):13727-32.
Vasopressin stimulated a 40% decrease in [32P]phosphatidylinositol 4,5-bisphosphate and a 15% decrease in [32P]phosphatidylinositol within 30 s of addition to hepatocytes prelabeled for 60 min with 32P. In hepatocytes prelabeled with [3H]inositol for 60 min, vasopressin produced 20% breakdown of phosphatidylinositol and 33% breakdown of phosphatidylinositol 4,5-bisphosphate within 30 s. There was a 40% increase in total phosphatidylinositol 4,5-bisphosphate within 30 s of vasopressin addition. Breakdown of phosphatidylinositol accounted for disappearance of 95% of the inositol lipid label. In hepatocytes from rats labeled in vivo with [3H]inositol, vasopressin stimulated 10% loss of labeled phosphatidylinositol. Loss of [32P]phosphatidylinositol due to vasopressin was followed by reincorporation of label to levels greater than control while 32P reuptake into phosphatidylinositol 4,5-bisphosphate did not exceed control values. With in vitro [3H]inositol-labeled hepatocytes, loss of label from the phosphoinositides was followed by reuptake of tritium label to control levels. In hepatocytes labeled in vivo with [3H]inositol, reuptake of [3H]inositol label did not occur. These data indicate that the hormone-sensitive pool of hepatocyte phosphoinositides can be labeled by both in vitro and in vivo procedures. Vasopressin induces a rapid decrease of labeled phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate within 30 s.
向预先用³²P标记60分钟的肝细胞中加入血管加压素后30秒内，[³²P]磷脂酰肌醇4,5 - 二磷酸减少40%，[³²P]磷脂酰肌醇减少15%。在预先用[³H]肌醇标记60分钟的肝细胞中，血管加压素在30秒内使磷脂酰肌醇分解20%，磷脂酰肌醇4,5 - 二磷酸分解33%。加入血管加压素后30秒内，总磷脂酰肌醇4,5 - 二磷酸增加40%。磷脂酰肌醇的分解占肌醇脂质标记消失的95%。在用[³H]肌醇在体内标记的大鼠肝细胞中，血管加压素刺激使标记的磷脂酰肌醇损失10%。血管加压素导致的[³²P]磷脂酰肌醇损失后，标记重新掺入的水平高于对照，而³²P重新摄取到磷脂酰肌醇4,5 - 二磷酸中未超过对照值。对于体外[³H]肌醇标记的肝细胞，磷酸肌醇中标记的损失后，氚标记重新摄取到对照水平。在用[³H]肌醇在体内标记的肝细胞中，未发生[³H]肌醇标记的重新摄取。这些数据表明，肝细胞磷酸肌醇的激素敏感池可以通过体外和体内程序进行标记。血管加压素在30秒内诱导标记的磷脂酰肌醇和磷脂酰肌醇4,5 - 二磷酸快速减少。
