Enhanced Thermolability in Anephric Rabbits

Uremic patients tend to have a lower than normal deep-body temperature. In addition, there is a clinical impression that uremic patients are also more thermolabile than healthy people; that is, in a warm environment, body temperature tends to be higher, and in a cold environment, body temperature tends to be lower than in healthy subjects. To test the hypothesis that uremia results in enhanced thermolability, nonoperated control (NO), nephrectomized (NX), and sham-nephrectomized (SHAM) rabbits were subjected to mild cold (5°C) and heat (30°C) stresses. At 48 hours postsurgery, the core temperature of NX rabbits was significantly lower than that of the NO or SHAM rabbits (P < .01). Exposure to 5°C resulted in a significant fall in body temperature of the NX (from 39.1 °C to 38.3°C; P < .05) rabbits compared to the NO rabbits. There was a tendency for body temperature of the SHAM rabbits to fall, and as a result, there was no significant difference in the change in body temperature between the SHAM and NX rabbits. Exposure to 30°C resulted in virtually no change in the core temperature of the NO or SHAM rabbits, but did result in a significant rise in core temperature of the NX rabbits (P < .02 and P < .01 for respective comparisons), as well as a significant increase in mortality rate (P < .02). Based on these data, we conclude that anephric animals are more thermolabile, and are less able to tolerate exposure to a warm environment, than are normal animals.