Abstract
The presence of extra-hepatic systems for uric acid production and their role in catecholamine-induced hyperuricemia were studied in eviscerated rats with functional hepatectomy. In these animals, the plasma uric acid level progressively increased with a decrease of allantoin, and isoproterenol subcutaneously administered in low doses produced an evident hyperuricemia. The effect of isoproterenol was seen even in nephrectomized animals, but all effects were abolished by pretreatment with allopurinol. Epinephrine and norepinephrine also produced hyperuricemia, though to a lesser extent than isoproterenol. Propranolol inhibited the hyperuricemic effects of isoproterenol and epinephrine, while phentolamine potentiated the effects of epinephrine. Electrical stimulation of the splanchnic nerve also produced hyperuricemia in eviscerated rats with functional hepatectomy, and this state was abolished by pretreatment with propranolol and by adrenalectomy but was not affected by pretreatment with phentolamine. Thus, beta adrenoceptor agonists stimulate production of uric acid in tissues other than the liver and the viscera, and hyperuricemia results. An effect similar to that on the uric acid level was also observed for the levels of plasma lactate, creatinine and glutamic oxalacetic transaminase in rats given isoproterenol.
