The adipokines of brown fat

Brown fat can convert chemical energy into thermal energy by uncoupling protein 1, and it has high activity in substrate oxidation. In general, the metabolism role of brown fat is attributed to its uncoupled respiratory and thermogenic functions. Recent studies have shown that BAT also has secretory function, and the secreted factors work locally or systemically by improving glucose tolerance and insulin sensitivity to affect metabolism, such as interleukin-6 (IL6), fibroblast growth factor-21 (FGF21) and neuregulin 4 (NRG4). Therefore, the identification of brown adipose-derived factors contributes to a comprehensive understanding of the role of brown fat in metabolism and further expands the potential therapeutic strategies for metabolic diseases. •Both typical and latest batokines are listed.•An ucp1-independent role for brown adipose tissue relying on these batokines is proposed.•Therapies of metabolic diseases are broadened by targeting the secreted factors.