ABSTRACT
Hibernation is a seasonal phenomenon in which the body temperature of the animal adjusts to the temperature of the nest. The lethargic state in winter is periodically interrupted by periods of arousal even though the ambient temperature remains low. During these periods, there is a release of norepinephrine in brown adipose tissue (BAT) which stimulates lipolysis in brown adipocytes by binding to membrane β-adrenergic receptors. The production of heat in BAT results from the combustion of fatty acids, which have three possible origins: they may be synthesized in BAT itself, be taken up from blood in fasting animals or derive from fatty acids transported in the form of triglycerides in lipoproteins bearing Apo CII. Total lipids of BAT decrease by 25% during the arousal phase, although they return to their initial levels within a few hours during activity. The chapter provides information on the replenishment of triglycerides in BAT on return of the hibernating garden dormouse to the euthermic state.
