Pharmacological studies of diuretics (4)

Changes of serum uric acid level by the successive administrations of thiazide diuretics and other drugs in rats and effects of uricosuric drugs in these rats were studied and the following results were obtained.1) On the serum uric acid level in normal rats, allopurinol and ketophenylbutazonehad significantly decreasing effect, but bucolome and probenecid had weak decreasing effect.2) On the serum uric acid level in acutely uric acid loaded rats, allopurinol, ketophenylbutazone, probenecid and bucolome had significantly decreasing effect, but sulphinpyrazone and chinophene had not steady effect.3) The hyperuricemia was induced by successive subcuteneously administrations of chlorothiazide, hydrochlorothiazide, adenine or uric acid for 2 weeks in rats.4) On the hyperuricemic rats explained above, allopurinol had strong and regular decreasing effect of serum uric acid level by the single dose of 100 mg/kg i. p. or successive administrations of 50 mg/kg i. p. for last 1 weeks. Ketophenylbutazone and bucolome had also significantly decreasing effect, but whether probenecid, phenylbutazone and sulphinpyrazone had weak decreasing effect or not.5) The strong decreasing effect of serum uric acid level of allopurinol on the acutely uric acid loaded rats or hyperuricemic rats which induced by successive admini-strations of uric acid suggest the other mechanisum in addition to xanthine oxidase inhibition of allopurinol.