Hyperuricemic effects of cholinergic agents in rats.

The hyperuricemic effect of cholinergic agents was studied in rats given potassium oxonate which inhibits urate oxidase and in functionally hepatectomized rats. Acetylcholine slightly increased plasma uric acid in the oxonate-treated animals, and the effect was markedly enhanced by pretreatment with physostigmine. Carbachol alone showed the hyperuricemic effect at a smaller dose than acetylcholine. The hyperuricemic effects of physostigmine plus acetylcholine and carbachol alone were also observed in eviscerated rats with nonfunctioning livers. Nephrectomy markedly potentiated cholinergic agent-induced hyperuricemia, and methylatropine but not hexamethonium apparently abolished the induction of hyperuricemia both in potassium oxonate-treated rats and in eviscerated rats with nonfunctioning livers and without kidneys. However, carbachol-induced hyperuricemia was not found in rats given allopurinol whose plasma levels of uric acid were maintained by exogenously administered uric acid. These results supported the ideas that the hyperuricemic effect of cholinergic agents is due to the stimulated production of uric acid and that uric acid production in tissues other than the liver and the gastrointestinal viscera is closely related to the induction mechanisms of hyperuricemia.