Creatol, an oxidative product of creatinine in hemodialysis patients

Creatol (CTL) is a product resulting from the reaction of creatinine (Cr) w ith the hydroxyl radical and is identified as a precursor of methylguanidin e (MG), a uremic toxin. In this study, we investigated serum CTL levels tog ether with those of Cr and MG in 66 patients who were on maintenance hemodi alysis (HD). Prior to dialysis, the mean serum levels of Cr, CTL and MG wer e 967 (= 11.1 mg/dl) +/- 267 mu M, 11.1 +/- 4.8 mu M and 5.8 +/- 2.9 mu M, respectively. The mean CTL level was about 1.1% that of Cr, and the CTL plu s MG level was about 1.4% that of the Cr level. The reduction rates of Cr, CTL and MG by a single HD were 62.6 +/- 6.1%, 71.0 +/- 10.3% and 51.9 +/- 1 1.6%, respectively. The CTL level at 0.5, 1 and 6 h after HD increased rapi dly by 20.7 +/- 8.7%, 31.7 +/- 14.7% and 80.1 +/- 27.3%, respectively. Ther e was a significant correlation between CTL or CTL/Cr and parathyroid hormo ne in patients who had just undergone parathyroidectomy. No significant cor relation was found between CTL or CTL/Cr and those factors which seems to b e related to the predialysis levels of reactive oxygen. Therefore, because of the good clearance of CTL and its rapid conversion to MG, its usefulness for the estimation of hydroxyl radical generation in HD patients is limite d.