The Lives and Times of Brown Adipokines

Brown adipose tissue (BAT) is responsible for adaptive non-shivering thermogenesis. Moreover, brown fat secretes regulatory factors, so-called brown adipokines, that have autocrine, paracrine, and endocrine actions. Brown adipokines are either polypeptides or nonpeptidic molecules including lipid molecules and microRNAs. The secretory properties of brown fat are essential for tissue remodeling adaptations to thermogenic necessities. The endocrine properties of brown adipokines are thought to contribute to the association between BAT activity and a healthy metabolic profile in relation to glucose and lipid homeostasis. The identification and characterization of brown adipokines may allow the discovery of circulating biomarkers of BAT activity in humans, and will lead to the development of candidate tools for therapeutic interventions in metabolic diseases. Brown adipose tissue (BAT) secretes a distinct pattern of regulatory factors, the so-called brown adipokines, that are distinct from the adipokines secreted by white adipose tissue. Brown adipokines with autocrine and paracrine actions are involved in the crosstalk between brown adipocytes and other cell types within BAT depots (e.g., preadipocytes, immune cells, vascular cells, and neuronal cells) that is necessary for tissue remodeling and adaptation to the thermogenic requirements of the body. The endocrine functions of brown adipokines help to explain the association between BAT activity and a healthy systemic metabolic profile, in addition to the intrinsic metabolite-oxidizing activity of brown fat.