抄録
Uric acid is present as monosodium urate (NaHU) for dissociation of about 99% in the blood and tissue fluid. NaHU being freely permeable through the capillary wall, the uric acid concentration is nearly equilibrated between blood and tissue fluid; consequently, to measure the serum uric acid level means indirect measurement of the uric acid concentration in the tissue fluid.
Since pathogenecity of uric acid in the organism is manifested by precipitation of NaHU following its saturation in the tissue fluid, we consider that the solubility of NaHU in the tissue fluid is an indispensable factor in determining the normal range of the serum uric acid level. However, the composition of tissue fluid is somewhat varied in the sites of body, and it is also difficult practically to collect tissue fluid for determination of the solubility of NaHU. In an attempt to solve this problem, we prepared an experimental solution consisting of composition similar to the tissue fluid and determined the solubility of NaHU in the solution to obtain an approximate value of the solubility of NaHU in the authentic tissue fluid. And the following results were obtained:
1) The saturated concentration of NaHU in the experimental tissue fluid of which protein level is 0 was 6.8 mg/dl at 37°C.
2) The saturated concentration of NaHU in the experimental tissue fluid of which protein level is 7.46 g/dl (same as serum) was 12.5 mg/dl at 37°C.
