Lipolytic activity in brown adipocytes during spontaneous weight cycles in dormice.

In vitro release of glycerol from isolated brown adipocytes into incubation medium was measured using axillary brown adipose tissue (BAT) removed from dormice during various phases of the infradian body weight cycle. Lipolytic activity in BAT was reduced during the weight loss phase in comparison to the weight gain phase. In the absence of deep and prolonged torpor, BAT does not appear to act as an effector of weight loss for hibernators undergoing large cyclical fluctuations in body energy content.