Alterations in hepatic gluconeogenesis, prostanoid, and intracellular calcium during sepsis

Objective: The metabolic alterations observed during sepsis maybe associate d with changes in local concentrations of intracellular calcium (Ca2+) and prostanoid synthesis in the liver. The authors studied hepatocyte intracell ular Ca2+ and the release of glucose. and prostanoid in an in-vivo murine l iver perfusion model. Methods: Sepsis was induced in anesthetized, fasted r ats by cecal ligation and puncture. (CLP, n = 42). Hepatic glucose release was studied in control (n = 10) and CLP (n = 10) groups using a nonrecircul ating liver perfusion model with and without lactate as gluconeogenic subst rate. Hepatocyte intracellular Ca2+ (n = 11) was measured using the selecti ve indicator Fura-a under basal and epinephrine (10(-5) M) stimulated condi tions. 6-Keto-prostaglandin F-1 alpha (6-Keto) and thromboxane B-2 (TxB(2)) were determined from liver perfusate by radioimmunassay (n = 11). Data wer e analyzed using t-tests and repeated-measures ANOVA. Results: Plasma gluco se was significantly lower in CLP groups compared with controls:(74.9 +/- 6 .6 vs 115.7 +/- 4.6 mg/dL, p < 0.05). Plasma lactate was:significantly high er in CLP vs controls (3.7 +/- 0.4 vs 1.4 +/- 0.1 mM, p < 0.05). Glucose re lease in isolated pei fused livers was significantly lower in CLP vs contro ls (8.5 vs 16 +/- 1.2 mu M/g/hr, p < 0.001). With the addition of lactate pyruvate to the perfusate, glucose output in CLP livers was significantly lower following 5 (9.9 +/- 0.7 vs 17.7 +/- 1.1 mu M/g/hr, p < 0.05) and 10 (11.9 +/- 1.2 vs 20.6 +/- 1.3 mu M/g/hr, p < 0.001) minutes of perfusion. T he basal level of intracellular calcium ([Ca2+](i)) in CLP rats (460.1 +/- 91.6 nM) was significantly higher than in control rats (196.3 +/- 35.5 nM) (p < 0.05). A significant increase(p < 0.05) in [Ca2+](i) occurred after th e addition of epinephrine in hepatocytes in control (196.3 +/- 35.5 vs 331. 8 +/- 41.4 nM) but not CLP (460.1 + 91.6 vs 489.4 +/- 105 nM) rats. 6-Keto was significantly lower in CLP compared with controls at 30 minutes (25.7 /- 3.9 vs 33.4 +/- 5.5 pg/mL, p < 0.05), whereas TxB(2) was not significant ly altered (52.1 +/- 34.7 vs 87.5 +/- 43.2 pg/mL). Conclusion: These result s demonstrate that CLP sepsis is associated with an increase in hepatocyte intracellular free Ca2+ concentration along with attenuation of hormone-med iated Ca2+ mobilization and hepatic gluconeogenesis. Key words: rat; cecal ligation and. puncture; hepatic glucose release; hepatocyte intracellular c alcium; 6-keto prostaglandin F-1 alpha; thromboxane B-2; plasma glucose; pl asma lactate; Liver perfusion.