Cyanate and temperature regulation in anephric rabbits.

Knochel and Seldin proposed that the lowered body temperature observed during uremia was caused by an elevation in the circulating levels of cyanate. To test this hypothesis, normal rabbits were infused with varying concentrations of sodium cyanate. Infusion of pharmacological doses of cyanate (plasma concentration rose to 1,080 +/- 70 microM, n = 5) resulted in reductions in body temperature similar to that found during uremia; however, when normal rabbits were nephrectomized the plasma cyanate concentration only rose from 3.7 +/- 1.6 to 18 +/- 1.8 microM (n = 8) by 1-day postnephrectomy (body temperature fell 0.33 +/- 0.1 degrees C, n = 6). Plasma cyanate concentration did not rise further on days 2 and 3 postnephrectomy, despite a continued fall in body temperature. Infusion of cyanate in control rabbits to plasma concentrations attained 1-3 days postnephrectomy did not result in a fall in body temperature. Based on the failure of pathophysiological concentrations of cyanate to cause a reduction in the body temperature of normal rabbits, we conclude that cyanate is not responsible for the lowered body temperature associated with the acute response to uremia.