HEPATIC INSULIN RESISTANCE DURING CANINE SEPSIS

Glucose dyshomeostasis and insulin resistance are well-documented characteristics of sepsis. The insulin resistance could be manifested in a decreased peripheral glucose uptake and/or an increased hepatic glucose output. To investigate the hepatic and peripheral responses to insulin in a three-day model of sepsis, 14 mongrel dogs were studied. Animals were randomly assigned to a SEPTIC (n = 5), SHAM (n = 4), or CONTROL (n = 5) group. Sepsis was induced in anesthetized dogs via a midline laparotomy with subsequent placement of a fecal-soaked gauze sponge around intestines. SHAM and CONTROL dogs were pair-fed with the SEPTIC dogs. On the third day, animals were anesthetized, intubated, and ventilated. Via a left-side laparotomy, electromagnetic flow probes were placed to measure hepatic arterial and portal venous blood flows. Cannulas were placed in femoral, portal, and hepatic veins and femoral artery to measure hepatic outputs of glucose, lactate, and oxygen during hyperinsulinemic-euglycemic clamps ranging from 0.4 to 4,000 mU insulin/min. Portal venous insulin concentrations in SEPTIC animals were significantly increased compared to CONTROL animals during 0.4 and 4 mU insulin/min infusions. An insulin infusion rate of 40 mU/min significantly decreased net hepatic glucose output (NHGO) in CONTROL animals but did not affect NHGO in SHAM or SEPTIC animals. An insulin infusion rate of 4,000 mU/min significantly decreased NHGO in all groups. An attempt to analyze the ED50 of the three dose-response curves was inconclusive. Glucose infusion rates (GIR) increased during insulin infusion but the GIR were not different between groups at any insulin infusion rate. These data suggest an hepatic insulin resistance (insensitivity) and do not support the occurrence of whole-body insulin resistance in this canine 3-day model of sepsis.