Concentração sérica de paratormônio intacto em cães com insuficiência renal crônica

Abstract

Estudou-se a ocorrência de hiperparatireoidismo secundário renal e determinaram-se as concentrações séricas de paratormônio intacto (PTHi-c), cálcio total e fósforo em 30 cães com insuficiência renal crônica (IRC) e em 40 cães sadios. Para a determinação do PTHi-c, foi utilizado o método imunofluorométrico, com o emprego de anticorpos anti-aminoterminal (extraídos de gema de ovo da galinha) e de anticorpos monoclonais anti-carboxiterminal (H5P10), marcados com Europium. As concentrações séricas de PTHi-c (717,23±469,13pg/ml no grupo IRC e 36,76±34,40pg/ml no grupo-controle; P=0,0001), cálcio total (11,46±2,03mg/dl no grupo IRC e 10,11±0,91mg/dl no grupo-controle; P=0,003) e fósforo (12,01±8,06mg/dl no grupo IRC e 4,33±0,74mg/dl no grupo-controle; P=0,0001) foram mais altas nos cães com IRC. Observou-se estreita correlação entre PTHi-c e fósforo (r=0,56; P=0,0006), o que não ocorreu entre PTHi-c e cálcio. Hipercalcemia em cães com alta concentração de PTHi-c demonstrou a possível ocorrência de hiperparatireoidismo terciário em 11 animais. A hiperfosfatemia pode indicar, de forma indireta, a ocorrência de hiperparatireoidismo secundário nos cães com IRC.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 anti-aminoterminal 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.