Circadian rhythms of urinary saturation levels of calcium oxalate and calcium phosphate in normal male individuals

Abstract

健常男性5名を対象に3回の異なる時期に, 蓚酸カルシウム, 燐酸カルシウム, 酸性燐酸カルシウムの飽和度をそれぞれ示すAP(CaOx)指数, AP(CaP)指数, AP(Bru)指数(Tiselius)を測定し, その飽和度の日内変動を検討した。就寝時以外2時間30分毎に採尿し, これらの指数を計算した。蓚酸カルシウムと酸性燐酸カルシウムの飽和度は5時～8時で最高値となった。燐酸カルシウム飽和度は二峰性で, 8時～10時30分と13時～18時に最高値となった。燐酸オクタカルシウムと水酸化アパタイトのイオン活量積も, AP(CaP)の値より求めたが, 燐酸カルシウムの飽和度と同様なパターンを示した

The circadian rhythms of the calcium oxalate, calcium phosphate, and brushite saturation levels as estimated by the AP(CaOx), AP(CaP), and AP(Bru) indices (Tiselius), respectively, were studied in 5 healthy males on three different occasions. These indices were calculated from the data of urinary specimens collected in 2.5-hour fractions except during sleep. The calcium oxalate and brushite saturation levels peaked between 5:30 and 8:00 am, and these were significantly higher than in the other periods. The calcium phosphate saturation level had two peaks that occurred between 8:00 and 10:30 am and between 1:00 and 6:00 pm. The ion-activity products of octacalcium phosphate and hydroxyapatite, calculated from the AP(CaP) index, exhibited a pattern similar to the AP(CaP) values, indicating a high risk of crystallization for both substances at around the same peak periods. In conclusion, early morning was found to be the high risk period for calcium oxalate and brushite crystallization, while two high risk periods for octacalcium phosphate and hydroxyapatite were detected between 8:00 and 10:30 am and between 1:00 and 6:00 pm.