Serum concentration of intact parathormone in dogs with chronic renal failure

The occurrence of renal secondary hyperparathyroidism was studied and serum intact parathormone (PTHi-c), total calcium and phosphorus were measured in thirty dogs with chronic renal failure (CRF) and in forty healthy dogs. The imunnofluorometric method was used for the PTHi-c assay, using antiaminoterminal antibodies ( obtained from chicken yolk) and anti-carboxiterminal monoclonal antibodies ( H5P10), marked with Europium. Mean value +/- SD of serum concentration of PTHi-c was 717.23 +/- 469.13pg/ml in CRF group and 36.76 +/- 34.40pg/ml in control group (P=0.0001); for total calcium it was 11.46 +/- 2.03mg/dl in CRF group and 10.11 +/- 0.91mg/dl in control group (P=0.003); and for phosphorus it was 12.01 +/- 8.06mg/dl in CRF group and 4.33 +/- 0.74mg/dl in control group (P=0.0001). The highest values were observed in CRF dogs. A positive correlation between PHTi- c and phosphorus was observed (r=0.56; p=0.0006), and no correlation was detected between PTHi-c and total calcium. In dogs with CRF, hypercalcemia in presence of high level of serum PTHi-c showed a possible indication of tertiary hyperparathyroidism in 11 animals. In conclusion, hyperphosphatemia could indirectly demonstrate the occurrence of secondary hyperparathyroidism in CRF dogs.