Hsu C, Jao H C, Yang S L, Hsu H K, Liu M S
Department of Physiology, Graduate Institute of Medicine, Kaohsiung Medical College, Taiwan.
Mol Cell Biochem. 1998 Apr;181(1-2):181-9. doi: 10.1023/a:1006853106320.
Changes in protein kinase C (PKC) (calcium- and phospholipid-dependent protein kinase) activity in rat liver during different metabolic phases of sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). Experiments were divided into three groups: control, early sepsis, and late sepsis. Early and late sepsis refers to those animals sacrificed at 9 and 18 h, respectively, after CLP. Hepatic PKC was extracted and partially purified by ammonium sulfate fractionation and DEAE-cellulose chromatography. PKC activity was assayed based on the rate of incorporation of 32p from [gamma-32P]ATP into histone. The results show that during early sepsis, both membrane-associated and cytosolic PKC activities remained relatively unaltered. During late sepsis, membrane-associated PKC was unaffected while cytosolic PKC activity was decreased by 19.5-34.4%. Kinetic analysis of the data on cytosolic PKC during late phase of sepsis reveals that the Vmax values for ATP, histone, Ca2+, phosphatidylserine, and diacylglycerol were decreased by 23.4, 22.1, 19.5, 25, and 34.4%, respectively, with no changes in their Km values. These data indicate that cytosolic PKC activity was inactivated in rat liver during late hypoglycemic phase of sepsis. Since PKC-mediated phosphorylation plays an important role in regulating hepatic glucose metabolism, an inactivation of cytosolic PKC may contribute to the development of hypoglycemia during late phase of sepsis.
研究了脓毒症不同代谢阶段大鼠肝脏中蛋白激酶C（PKC，钙和磷脂依赖性蛋白激酶）活性的变化。通过盲肠结扎和穿刺（CLP）诱导脓毒症。实验分为三组：对照组、早期脓毒症组和晚期脓毒症组。早期和晚期脓毒症分别指CLP后9小时和18小时处死的动物。通过硫酸铵分级分离和DEAE - 纤维素色谱法提取并部分纯化肝脏PKC。基于[γ - 32P]ATP中32P掺入组蛋白的速率测定PKC活性。结果表明，在早期脓毒症期间，膜相关和胞质PKC活性相对未改变。在晚期脓毒症期间，膜相关PKC未受影响，而胞质PKC活性降低了19.5 - 34.4%。脓毒症晚期胞质PKC数据的动力学分析表明，ATP、组蛋白、Ca2 +、磷脂酰丝氨酸和二酰基甘油的Vmax值分别降低了23.4%、22.1%、19.5%、25%和34.4%，而它们的Km值没有变化。这些数据表明，在脓毒症晚期低血糖阶段，大鼠肝脏中的胞质PKC活性被灭活。由于PKC介导的磷酸化在调节肝脏葡萄糖代谢中起重要作用，胞质PKC的失活可能有助于脓毒症晚期低血糖的发生。
