Utilization of endogenous lipids and glycogen in the perfused rat heart: effects of hypoxia and epinephrine.

The interaction of hypoxia and catecholamines in the regulation of heart tissue lipid and glycogen utilization was studied in isolated perfused rat hearts with lipids prelabeled in vivo with [1-14C]palmitate. In well oxygenated hearts, epinephrine stimulated triglyceride mobilization by approximately 2-fold. In hypoxia, net mobilization of triglycerides was negligible with or without added epinephrine. Thus, the effect of hypoxia to reduce triglyceride mobilization would favor the accumulation of neutral lipid in the myocardium Glycogenolysis was markedly enhanced in hypoxic hearts and epinephrine produced little further stimulation. In well oxygenated hearts, epinephrine increased glycogen mobilization by 3-fold.