Cardiovascular research
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Cardiovascular research · Jan 1990
Insulin and beta adrenergic effects during endotoxin shock: in vivo myocardial interactions.
STUDY OBJECTIVE - Catecholamine concentrations are raised during endotoxin shock and may be responsible for myocardial insulin resistance in such a condition. The purpose of the investigation was to examine the effect of insulin on myocardial contractility and glucose uptake in the presence of beta adrenergic blockade during endotoxin shock. DESIGN - Endotoxin shock was obtained in dogs by giving S Typhimurium endotoxin intravenously (1 mg.kg-1) and the cardiac responses to insulin were determined under hyperinsulinaemic (4 U.min-1) euglycaemic clamp conditions during continuous beta adrenergic blockade (propranolol 150 micrograms.kg-1 + 5 micrograms.kg-1.min-1). ⋯ In controls, insulin increased myocardial performance; in shock this response was attenuated. CONCLUSIONS - The findings confirm that the myocardium becomes less responsive to the glucose uptake stimulating and positive inotropic effects of insulin during endotoxin shock. The data show that beta adrenergic activity is responsible for the increased contractile state of the heart during acute endotoxin shock, but is not the cause of the observed insulin resistant state.