Differences in the lipolytic and cyclic AMP accumulative action of noradrenaline-theophylline and norephedrine-theophylline.

The action of theophylline derivatives (-)-7-2-(2-hydroxy-1-methyl-2-phenyl-ethylamino)-ethyl-theophyl-line (cafedrine) and 7-2-2-(3,4-dihydroxy-phenyl-2-hydroxy-ethylamino)-ethyl-theophylline (theodrenaline) on free fatty acids (FFA) levels in rat blood serum and on cyclic AMP (cAMP) accumulation and FFA mobilization in isolated fat cells has been studied and compared to the action of a noradrenaline plus aminophylline mixture (NAA). A significant in vivo increase of FFA appeared 15 min after NAT and 90 min after NET i.p. administration. NAA was active at both times. Unlike NET, NAT stimulated in vitro FFA mobilization and cAMP accumulation: NAA action was however stronger. NAT-mediated cAMP accumulation, but not that which was NAA-induced, was totally inhibited by timolol. Our results suggest the existence of a beta-adrenergic mechanism for NAT and a tyraminic mechanism for NET. A theophyllinic action dos not seem to apply to either drug.