Inhibition of Lipolysis Reduces [~l-Adrenoceptor- Mediated Thermogenesis in Man

The purpose of the study was to investigate whether the increase in energy expenditure and lipid oxidation during I~l-adrenergic stimulation is caused by the concomitant increase in iipolysis. Twelve healthy male subjects participated in three trials: no-LIP/-, inhibition of lipolysis by pretreatment with acipimox followed by saline infusion;-/BETA, no pretreatment, with dobutamine infusion to stimulate I~l-adrenoceptors; and no-LIP/BETA, pretreatment with acipimox followed by dobutamine infusion. Inhibition of lipolysis did not affect baseline energy expenditure, but decreased lipid oxidation and increased carbohydrate oxidation. Energy expenditure and lipid oxidation increased significantly during 13~-adrenergic stimulation, but this increase was significantly smaller when iipolysis was inhibited ([baseline v infusion period] energy expenditure:-/BETA