CIRCADIAN PERIODICITY OF URINARY INHIBITOR OF CALCIUM-OXALATE CRYSTALLIZATION IN HEALTHY INDIANS AND RENAL STONE FORMERS

The inhibitory activity (IA) of calcium oxalate crystallization was in vestigate in healthy Indians and renal stone formers. A marked circadi an rhythm was observed in men and women of both groups. The rhythm pat tern was similar on the basis of sex; however, it was different in sto ne formers as compared to normals. The acrophase for crystallization o f calcium oxalate was observed, respectively, at 05.43 and 05.52 h in healthy men and women, and at 09.52 and 09.23 h in male and female ren al stone formers. Moreover, the acrophase of percent inhibition by IA was observed at 17.44 and 17.52 h in healthy participants and at 21.52 and 21.27 h in male and female stone formers, respectively. Therefore , the acrophase suggests a highest risk of crystallization during the morning hours and a minimum one during the evening hours. The day-nigh t rhythmic pattern of urinary calcium, magnesium and phosphorus is dis cussed in relation to the rhythm of IA.