Myocardial Lipases and Catecholamines in Burn Shock 1

Abstract

Summary

In anesthetized dogs subjected to 4 hr of shock from infrared burns, lipolytic activity of cardiac muscle was found significantly below the activity determined in normal heart muscle. Myocardial homogenates from control and burned dogs responded to the addition of epinephrine with an increase in rate of lipolysis after incubation for 10 min. Incubation of the media for 1 hr showed a further increase in lipolysis, although no difference was noted in activity between epinephrine-treated and untreated homogenates from either the control or burn group of dogs. The addition of inhibitors or activators to the lipolytic mixture prepared from normal hearts suggested that cardiac lipolytic activity results from both an epinephrine-sensitive lipase and a lipoprotein lipase. The epinephrine-sensitive lipase could not be classified as a monoglyceride lipase, since epinephrine as well as ATP and cyclic AMP failed to increase the rate of lipolysis in cardiac muscle homogenates containing monopalmitin substituted for Ediol as a substrate.

Myocardial norepinephrine and epinephrine levels in burned dogs were not different from those found in control dogs. The absence of a change in these cardiac catecholamines leaves the possibility that other humoral or toxic substances may be responsible for altering myocardial lipolysis in burn shock.