Blood and liver lipids in torpid and aroused little brown bats, Myotis lucifugus

1. 1. Levels of serum and liver lipids were determined in torpid and aroused (4 hr post-torpor) Myotis lucifugus captured during hibernation. 2. 2. Serum cholesterol and triglyceride concentrations were not affected by arousal. 3. 3. The serum phospholipid concentration decreased 58 per cent and the serum free fatty acid concentration increased 266 per cent following arousal. 4. 4. Liver total lipid concentration decreased 68 per cent after arousal, but there was no change in liver weight. 5. 5. The decrease in the liver total lipid concentration was due to decreases in the cholesterol (87 per cent), triglyceride (73 per cent), phospholipid (54 per cent) and free fatty acid (90 per cent) concentrations.