Kinetics of PTH metabolism and PTH fragments in chronic renal failure

Distribution and metabolic degradation of bPTH was studied in man after infusion of 400 U bPTH and blood sampling up to 2h. Disappearance rates of intact 1-84 bPTH, carboxyl- and amino-regional peptides were calculated for healthy subjects (n = 12); patients suffering from moderate (GFR 15--30 ml/min, n = 4) and advanced (GFR less than or equal to 10 ml/min, n = 36) chronic renal failure; and bilateral nephrectomized patients (n = 3). Two components with a rapid and a slow disappearance rate can be separated ("distribution", "metabolism"). Half-lives are found to be in the range known from animal experiments with marked differences between intact 1-84 PTH and peptide fragments. Influence of impaired renal function on metabolic turnover rates of PTH is given.