INHIBITION OF HORMONAL-STIMULATION OF LIPOLYSIS IN PERFUSED RAT-HEART BY KETONE BODIES

The interaction of ketone bodies, acetate and octanoate with isoproterenol-stimulated lipolysis (glycerol output) was studied in the Langendorff perfused rat heart. Increasing perfusate concentrations of β-hydroxybutyrate or acetoacetate progressively and completely inhibited the isoproterenol-augmented glycerol output of the perfused rat heart. Likewise, acetate and octanoate suppressed the lipolytic response to isoproterenol but the maximal inhibition by these latter compounds amounted to approximately 50% of the isoproterenol effect. Isoproterenol elevated the protein kinase activity ratio, an index of heart cyclic AMP, at all concentrations of ketone bodies studied, including those at which a complete inhibition of the isoproterenol-stimulated glycerol release occurred. Thus, ketone bodies have the ability to inhibit isoproterenol-stimulated lipolysis in the isolated perfused rat heart even in the presence of elevated protein kinase ratios. © 1978.