BROWN ADIPOSE-TISSUE TEMPERATURE IN LEAN AND OBESE RATS DURING EXERCISE

OBJECTIVE: To determine the extent to which brown adipose tissue (BAT) heat output is influenced by treadmill exercise. DESIGN: The aortic b lood core and interscapular BAT temperatures were recorded continuousl y during a short bout of intense exercise (different for each rat stoc k) in a treadmill and the ensuing 1-h recovery, sampling blood flows a t timed intervals. SUBJECTS: Conscious Wistar, Zucker lean and Zucker obese rats. MEASUREMENTS: Aortic a nd interscapular BAT temperatures a nd tissue blood flow. RESULTS: Basal mean temperatures were highest fo r Wistar. Exercise provoked increases in aortic core temperatures in a ll three groups, slowly cooling off during recovery. Exercise and/or f atigue induced increases (vs aortic core temperature) of IBAT temperat ure. The effects were less marked in obese rats. CONCLUSION: Increases in BAT temperatures induced by exercise were counteracted by parallel decreases in blood flow, resulting in insignificant losses of heat fr om interscapular BAT during exercise and recovery both in lean and obe se rats.