Glucose utilisation in the lungs of septic rats

Sequestration and degranulation of leucocytes in the pulmonary microcircula tion is considered to be a key event in the development of acute respirator y distress syndrome in patients with sepsis. Glucose serves as the main sou rce of energy in activated leucocytes. The aim of this study was to assess whether glucose utilisation in the lungs can be used as an indicator of pul monary leucocyte accumulation in an experimental model of sepsis of intra-a bdominal origin. Sepsis was induced in rats by abdominal implantation of a gelatine capsule containing bacteria and rat colonic contents. Empty gelati ne capsules were implanted in control animals. Animals were studied 6 and 1 2 h after sepsis induction. Glucose utilisation was measured as the tissue uptake of fluorine-18-fluorodeoxyglucose ((18)FDG) 1 h after intravenous in jection of the tracer. Micro-autoradiography was also performed after injec tion of tritiated deoxyglucose. We found increased uptake of (18)FDG in the lungs of septic animals. The uptake also increased with time after sepsis induction. (18)FDG uptake in circulating leucocytes was increased in septic animals compared with controls, and micro-autoradiography showed intense a ccumulation of deoxyglucose in leucocytes in the lungs of septic animals. W e conclude that glucose utilisation is increased in the lungs of septic rat s. Measurements of pulmonary glucose utilisation as an index of leucocyte m etabolic activity may open new possibilities for studies of the pathophysio logy of sepsis and for evaluation of therapeutic interventions.