Impact of sodium-potassium citrate therapy on the circadian rhythm of urinary uric acid and urate saturation in normal individuals

Abstract

健常男性5名を対象に, クエン酸塩(3g分3, 4g分4, あるいは, 9g分3)を投与し, 尿酸と尿酸塩の尿中飽和度の日内変動を検討した。Marshall and Robertsonの相対過飽和度により測定した。尿酸の相対過飽和度は日内で変動し(平均±SD:-1.297±1.763), 5時30分～8時で最高値となり, 結晶生成度積を越えた。クエン酸投与により最高値は低下傾向を示した。尿345サンプルの分析結果で, 尿酸の不安定過飽和状態は46サンプルに見られ, その83%は午前5時30分～8時に見られた。酸性尿酸ナトリウムの相対過飽和度は日内で変動し(平均±SD:0.329±0.305), 午前8時～10時30分で最高値となり, クエン酸投与により, その飽和度は上昇したが, 準安定過飽和状態以下であった。酸性尿酸アンモニウムの相対過飽和度も日内で変動し(平均±SD:0.087±0.301), 午前5時30分～8時に最高値となり, クエン酸投与により飽和度は低下し, 一日中準安定過飽和状態以下であった

The circadian rhythm of the urinary saturation of uric acid, sodium acid urate, and ammonium acid urate was studied in 5 normal healthy male volunteers before and during 5 days of treatment with sodium-potassium citrate (1 g t.i.d., 1 g q.i.d., or 3 g t.i.d.). Urinary saturation was estimated on the relative supersaturation scale of Marshall and Robertson. Uric acid relative supersaturation varied during the day (mean +/- SD: -1.297 +/- 1.763) and peaked above the formation product between 5:30 and 8:00 am. The peak level was reduced (but not significantly) by each treatment regimen in comparison with the control day. Overall, critical supersaturation with uric acid was noted in 46 (13%) out of 345 urine specimens, occurring mostly (83%) between 5:30 and 8:00 am. The sodium acid urate relative supersaturation also varied during the day (mean +/- SD: 0.329 +/- 0.305) and peaked below the formation product between 8:00 and 10:30 am. It was increased by each regimen (significantly by the 3 g t.i.d. regimen), but mostly remained in or below the metastable zone. The ammonium acid urate relative supersaturation also varied (mean +/- SD: 0.087 +/- 0.301) and peaked below the formation product between 5:30 and 8:00 am. The level was decreased by each regimen and remained in or below the metastable zone throughout the day. In conclusion, the early morning period was the time with the highest risk of urinary uric acid supersaturation, but this supersaturation could be reduced (although not significantly) by treatment with alkali citrate.(ABSTRACT TRUNCATED AT 250 WORDS)