Hydroxyproline excretion following renal transplantation: comparison with values found in primary hyperparathyroidism.

The amounts of total hydroxyproline (THP), free hydroxyproline (FHP) and non-dialysable hydroxyproline (NDHP) excreted in the urine by six patients with chronic renal failure who received kidney transplants and six patients with primary hyperparathyroidism were studied. Following transplantation three of the four patients with radiological evidence of hyperparathyroidism developed hypercalcaemia and excreted more than 360 mumol THP/24 hours on at least one occasion. The remaining patients were normocalcaemic and excreted less THP and a higher proportion of NDHP. In all patients with primary hyperparathyroidism, THP excretion fell after adenoma removal but there was an increased excretion of NDHP:THP. It is suggested that studies of hydroxyproline excretion may contribute to clinical assessment of healing of renal osteodystrophy and involution of the parathyroid glands after renal allograft transplantation.