Temperature preference of genetically obese (ob/ob) mice.

Genetically obese (ob/ob) and lean mice selected their preferred ambient temperature in a thermal gradient. Preferred ambient temperature was defined as that ambient temperature which the mice selected for sleep during daylight hours. Lean mice selected a temperature of 31.2 degrees C which resulted in a body temperature (36.7 degrees C) not greatly different from the pretest body temperature of 36.4 degrees C. Obese mice selected 29.4 degrees C which resulted in a body temperature of 36.8 degrees C, 1.8 degrees C above the pretest body temperature of 35.0 degrees C. These data indicate that obese mice select an ambient temperature that results in a body temperature no different from that of lean mice. The selection by obese animals of an ambient temperature significantly lower than that of lean mice but which results in the same body temperature may reflect an effect of adiposity on heat loss. There is no evidence of a diminished thermoregulatory set-point in obese mice.