Regulation of Thermogenic Capacity in White and Brown Adipose Tissues by Chronic Endurance Exercise and High-Fat Diet

This study investigated the effects of high-fat (HF) diet and chronic endurance exercise (Ex) on the regulation of thermogenic capacity in both brown adipose tissue (BAT) and subcutaneous (SC) white adipose tissue (WAT), and how it affects whole-body energy expenditure (EE). Analysis of tissue mass, PGC-1α and UCP-1 content, presence of multilocular adipocytes and palmitate oxidation revealed that HF diet increased the thermogenic capacity of BAT, while Ex suppressed it. Conversely, Ex induced the browning of the SC WAT, indicated by an increased number of multilocular adipocytes, as well as PGC-1α and UCP-1 content, and palmitate oxidation, whereas HF diet attenuated this effect. Despite reducing thermogenic capacity of BAT, Ex increased whole-body EE during the dark cycle. We propose that exercise-induced browning of SC WAT reduces thermogenic capacity in core body regions to manage the increased heat production of exercise, and increases it in peripheral regions to adjust metabolic rate.