• acute renal failure;
  • calcium metabolism;
  • feline;
  • PTH


Objective: To measure serum parathyroid hormone (PTH) and 25-hydroxyvitamin D3 concentrations in cats with urethral obstruction.

Design: Prospective single cohort study.

Setting: University affiliated veterinary teaching hospital.

Animals: Male cats with urethral obstruction.

Interventions: Routine blood samples drawn from male cats with urethral obstruction.

Measurements and main results: Measured variables included blood gas parameters, plasma sodium, potassium, chloride, and ionized calcium concentrations, as well as serum blood urea nitrogen, creatinine, phosphorus, PTH, and 25-hydroxyvitamin D3 concentrations. PTH was inversely correlated with ionized calcium and positively correlated with serum phosphorus. No discernable relationship could be found between 25-hydroxyvitamin D3 and any of the measured parameters.

Conclusions: Lack of parathyroid response does not appear to be the underlying mechanism for ionized hypocalcemia in cats with urethral obstruction.