SOLUBILITY OF URIC-ACID AND SUPERSATURATION OF MONOSODIUM URATE - WHY IS URIC-ACID SO HIGHLY SOLUBLE IN URINE
SOLUBILITY OF URIC-ACID AND SUPERSATURATION OF MONOSODIUM URATE - WHY IS URIC-ACID SO HIGHLY SOLUBLE IN URINE
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DOI：
10.1016/s0022-5347(17)39003-1
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发表时间：
1989-10-01
影响因子：
6.6
通讯作者：
TAKEUCHI, M
中科院分区：
文献类型：
--
作者：
IWATA, H;NISHIO, S;TAKEUCHI, M
在37 ℃下，在生理尿pH范围内，在含有150 mM钠的缓冲溶液中，研究了尿酸的溶解度和尿酸盐（NaU）过饱和的稳定性。尿酸的溶解度随着pH的升高而增加，并且在低于6.6的pH范围内孵育7天期间，总溶解尿酸盐（未解离尿酸+尿酸盐阴离子）浓度没有变化。在此pH范围内，未解离尿酸的计算浓度是恒定的（约6 mg/L）。dl.）。因此，随着pH值的升高，尿酸溶解度的增加完全取决于尿酸盐阴离子的增加。220毫克。DL.尿酸在pH 7.0时可溶解24小时。但培养7天后，总溶解尿酸盐浓度降至16 mg/L。DL.由于NaU结晶。NaU过饱和的稳定性不仅取决于钠和尿酸盐阴离子的浓度，而且还取决于时间和pH值。当尿酸单钾晶体孵育7天，总溶解的尿酸盐浓度下降根据NaU结晶; pH值越高，越显着的减少。至少有80毫克。DL.的总溶解尿酸盐在24小时内稳定至pH 8.2。这些发现可以很好地解释为什么NaU晶体很少在正常尿液中形成。尿潴留和/或病理性高尿pH可能导致NaU结晶。
The solubility of uric acid and the stability of supersaturation of monosodium urate (NaU) were studied in buffer solutions containing 150 mM sodium in the physiological urinary pH range at 37C. The solubility of uric acid increased with the rise in pH, and the total dissolved urate (undissociated uric acid + urate anion) concentration did not change during seven-day incubation in the pH range below 6.6. In this pH range, the calculated concentration of undissociated uric acid was constant (about six mg./dl.). Consequently, the increasing solubility of uric acid with the rise in pH depended solely on the increase of urate anion. As much as 220 mg./dl. of uric acid could be dissolved for 24 hours at pH 7.0. But following seven-day incubation the total dissolved urate concentration decreased to 16 mg./dl. due to NaU crystallization. The stability of NaU supersaturation depended not only on the concentration of sodium and urate anion but also on time and pH. When monopotassium urate crystals were incubated for seven days, the total dissolved urate concentration decreased according to NaU crystallization; the higher the pH, the more marked the decrease. However, at least some 80 mg./dl. of total dissolved urate was stable up to pH 8.2 within 24 hours. These findings can well explain why NaU crystals are seldom formed in the normal urine. Urinary stasis and/or pathological high urinary pH may cause NaU crystallization.