Adrenergic regulation of the plasma levels of purine metabolites in the rat

The effects of i.v. infusions of catecholamines on the plasma levels of uric acid and allantoin were investigated in the conscious rat. Isoproterenol and epinephrine, in this decreasing order of potency, remarkably elevated both uric and allantoin levels. Norepinephrine did not affect these purine metabolite levels. These effects of isoproterenol and epinephrine were completely abolished by propranolol. Phentolamine, on the contrary, slightly potentiated the effects of epinephrine. In contrast to i.v. fusion, s.c. injection of epinephrine had no effect, but, after prior treatment of animals with phentolamine, elicited striking increases in the plasma purine metabolite levels. Catecholamines thus caused hyperuricemia with a rise in plasma allantoin, both effects being mediated via beta-adrenoceptors and alpha-adrenergic mechanism sometimes functions in such a manner as to mask or inhibit this beta-mediated response.