Brown adipose tissue thermogenesis above the lower critical temperature

Area of Science:

• Physiology
• Metabolism
• Thermogenesis

Background:

• Brown adipose tissue (BAT) plays a crucial role in thermogenesis.
• The thermogenic capacity of BAT may vary with environmental temperature and diet.
• Understanding BAT's response to heat acclimation and diet is vital for metabolic research.

Purpose of the Study:

• To investigate the effects of heat acclimation on brown adipose tissue (BAT) characteristics at thermoneutrality.
• To examine the impact of a cafeteria diet on BAT mass and function in heat-acclimated rats.
• To determine if diet-induced thermogenesis occurs at thermoneutral temperatures.

Main Methods:

• Comparison of IBAT (interscapular brown adipose tissue) mass, gross composition, and GDP-binding in heat-acclimated rats versus controls.
• Administration of a cafeteria diet to rats at thermoneutral ambient temperature.
• Assessment of BAT thermogenesis and diet-induced thermogenesis.

Main Results:

• Heat-acclimated rats exhibited lighter IBAT deposits with altered composition and reduced GDP-binding compared to controls.
• A cafeteria diet significantly increased IBAT mass and GDP-binding in rats at thermoneutrality.
• These findings suggest a thermal disactivation of BAT following heat acclimation.

Conclusions:

• BAT thermogenesis at thermoneutrality is not minimal and can be modulated by diet.
• Diet-induced thermogenesis is possible even at thermoneutral ambient temperatures.
• BAT's adaptive capacity to dietary changes persists despite prior heat acclimation.