Specific aims of this proposal are: a) relating changes in cellular calcium homeostasis to prevailing derangements in the hormonal regulation of some aspects of carbohydrate and lipid metabolism at the cellular level in sepsis, and b) helping to define the extent to which these changes cna be attributed to endotoxin actions. Some of these alterations also occur in trauma and burn injury, while others do not. A clinically relevant form of experimental peritonitis will serve as a model for intra-abdominal sepsis. Endotoxicosis will be produced by i.v. injection of a bolus of endotoxin and also by slow delivery of endotoxin via an osmotic minipump over a period of several hours. The latter is a novel approach. Perturbations in calcium homeostasis and selected metabolic parameters will be investigated in isolated adipocytes and hepatocytes. Calcium uptake and efflux will be monitored in whole cells. The uptake and release of free CA++ will be quantitated in subcellular fractions (plasma membrane, mitochonria and endoplasmic reticulum) with antipyrylazo III in a dual wavelength spectrophotometer. Calcium contents of tissues, cells and organelles will be measured by atomic absorption spectrometry. In adipocytes catecholamine-stimulated lipolysis and insulin-stimulated glucose oxidation and antilipolysis will be assessed. In hepatocytes glycogenolysis as well as catecholamine and glucagon-stimulated gluconeogenesis from various substrates will be followed. The proposed studies will further our understanding of the pathophysiology of sepsis. By possibly implicating derangements in CA++ fluxes as mediating mechanisms of metabolic complications in the septic state, we may provide a rational basis for the use of calcium antagonists (e.g. Verapamil) and/or substances of calcium ionophoric activity as beneficial therapeutic agents in septic patients.
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