Fed and fasting thermoregulation in ob/ob mice

Area of Science:

• Physiology
• Genetics
• Metabolism

Background:

• Thermoregulation is crucial for energy balance.
• Obesity is often associated with metabolic dysregulation.
• Understanding factors influencing body temperature is vital for metabolic research.

Purpose of the Study:

• To investigate the impact of genotype (ob/ob mutation) and gender on body temperature regulation in mice.
• To compare thermoregulation between lean and obese mice under different feeding conditions (ad libitum feeding and fasting).
• To explore the role of hypothermia in energy conservation during starvation.

Main Methods:

• Measurement of body temperatures in mature lean and obese C57BL/6J mice.
• Experimental conditions included postprandial state, ad libitum feeding, and a 3-day fasting period.
• Body temperature was recorded every 24 hours during fasting.

Main Results:

• Obese mice displayed lower body temperatures (1.0-1.4°C) compared to lean mice during feeding.
• During fasting, obese mice exhibited greater hypothermia than lean controls.
• Obese females showed a pronounced drop in body temperature (5°C) within 24 hours of starvation, exceeding other groups.

Conclusions:

• Both genotype (ob/ob mutation) and gender significantly influence thermoregulation in mice.
• Lower body temperatures in obese mice contribute to energy storage under normal conditions.
• Hypothermia in females of both phenotypes enhances energy conservation during food scarcity, potentially preserving body mass and increasing fat stores.