Differential inhibition of lipolysis in human adipose tissue by adrenergic beta receptor blocking drugs.

The effects of various adrenergic beta receptor agonists and antagonists on lipolysis (measured as glycerol release) in human adipose tissue in vitro were studied. Of the agonists investigated, the potency rank order was isoproteronol greater than norepinephrine greater than salbutamol. Adrenergic beta receptor blocking drugs inhibited catecholamineinduced lipolysis competitively. Propranolol was the overall most effective compound, followed by metoprolol, alprenolol and practolol, whereas butoxamine and H35/25 were weak inhibitors. The results indicate that the adrenergic reciptor mediating lipolysis in human adipose tissue is of type beta-1. Basal and theophylline-induced lipolysis was reduced when higher concentrations of these drug were used.