Primary hyperparathyroidism and hyperuricaemia and bone turnover
As the major end product of purine metabolism urate is produced by most adults at the rate of 700 mg/day. Although a small proportion of the urate pool may by derived from the diet the greatest amount results from tissue breakdown. Both hyperuricaemia and gout occur with increased frequency in hyperparathyroidism (PHPT). PHPT is associated with a high bone turnover and increased turnover of nucleic acid of cellular origin. Urate metabolism was studied in 106 patients with PHPT. They had compared to controls significantly higher serum urate and reduction of the clearance of urate. In 28 of the tested patients with PHPT serum urate was increased above normal limits. Six months after parathyreoidectomy serum urate fell significantly from 379.3±67 to 270.7±56 μmol/l in 42 patients where urate measurements were available before as well after surgery. Both serum B-ALP and CTx were increased in our patiens with PHPT as the result of the enhanced bone turnover. Serum urate levels did not correlate with severity of skeletal changes expressed by serum B-ALP and CTx. We did not find any correlations between serum urate level and biochemical variables of bone turnover in 106 patients with PHPT. Serum urate level does not correlate with severity of skeletal changes expressed by B-ALP and CTx. These results suggest that parathormone does not increase the part of the urate pool coming from the nucleic acids of the increased bone metabolism.