REVERSIBILITY OF PARATHYROID-GLAND SUPPRESSION IN CAPD PATIENTS WITH LOW I-PTH LEVELS

The i-PTH response to changes in the peritoneal calcium balance was st udied prospectively in a group of 13 stable CAPD patients, who presuma bly had adynamic bone disease, with low or normal i-PTH values and low aluminum in plasma. Five days after the reduction of dialysate calciu m concentration from 1.75 mmol/l to 1 mmol/l, there was a significant elevation in the serum i-PTH. These increased PTH levels returned to b aseline values when patients were changed to the 1.75 mmol/l Ca soluti on (p = 0.004). The changes in i-PTH mirrored the changes in peritonea l calcium balances. These results support the notion that the low or n ormal levels of i-PTH frequently seen in peritoneal dialysis patients are due to the hypercalcemic effects of the standard peritoneal dialys is solutions; in these patients, the parathyroid hormone production is normal since negative peritoneal balances of calcium are associated w ith an increase in serum i-PTH.