A RAPID HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE ANALYSIS OF CHOLINE IN HUMAN PLASMA AND PERITONEAL-DIALYSIS EFFLUENT - APPLICATION IN THE ASSESSMENT OF CHOLINE LOSS IN CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

Mesothelial cells lining the peritoneal cavity utilize choline in the synthesis of a phosphatidylcholine-rich material thought to play a rol e in peritoneal homeostasis. This function is particularly important f or patients undergoing continuous ambulatory peritoneal dialysis (CAPD ). To assess choline loss in these patients, we measured choline in pl asma and peritoneal dialysis effluent (PDE) by a rapid high performanc e liquid chromatography (HPLC) procedure that combined electrochemical detection with an immobilized enzyme reactor. Chromatography was perf ormed directly on plasma and PDE ultrafiltrates. In 30 patients, the a mount of choline lost to the dialysate was 129 +/- 49 mumol per day an d 32 +/- 8 mumol per dwell (mean +/- SD). The average plasma choline c oncentration was 22.5 mumol/L, a value somewhat higher than the mean v alue reported for normal adults (9 mumol/L). The average PDE choline c oncentration was 14 mumol/L. There was a positive correlation between daily choline loss of dialysate and plasma choline concentrations (r = 0.826).