Inactivation of protein kinase C in rat liver during late hypoglycemic phase of sepsis

• Published in: Molecular and cellular biochemistry Vol. 181; no. 1-2; pp. 181 - 189
• Main Authors: Hsu, C, Jao, H C, Yang, S L, Hsu, H K, Liu, M S
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.04.1998
• Subjects: Ammonium; Animals; ATP; Cell Membrane - enzymology; Cellulose; Cytosol - enzymology; Fractionation; Hypoglycemia - enzymology; Inactivation; Kinases; Kinetics; Liver - enzymology; Magnesium Chloride - pharmacology; Male; Protein Kinase C - isolation & purification; Protein Kinase C - metabolism; Proteins; Rats; Rats, Sprague-Dawley; Sepsis; Sepsis - enzymology
• ISSN: 0300-8177; 1573-4919
• 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.