Adipokines in glucose and lipid metabolism

Abstract

Adipokines are proteins secreted by adipose tissue to regulate glucolipid metabolism and play vital roles in our body. Different adipokines have more than one endocrine function and be divided into several different categories according to their functions, including adipokines involved in glucolipid metabolism, the inflammatory response, insulin action, activation of brown adipose tissue (BAT) and appetite regulation. Multiple adipokines interact with each other to regulate metabolic processes. Based on the recent progress of adipokine research, this article discusses the role and mechanism of various adipokines in glucolipid metabolism, which may provide new ideas for understanding the pathogenesis and improving the treatment of various metabolic diseases.

Keywords: Insulin resistance; adiponectin; appetite; inflammation; leptin.

Figure 1.

Adiponectin and insulin signalling. APPL1 interacts with AdipoR1 or AdipoR2 and mediates the activation of multiple pathways including PPAR-α, AMPK and p38 MAPK by adiponectin, then triggers a cascade of biological responses. Most of the metabolic effects of insulin are mediated by PI3K/AKT pathway. APPL1 enhances crosstalk between the insulin and adiponectin signalling pathways, by promoting the interaction of IRS1/2 and insulin receptor.

Figure 2.

a. White adipocytes contain large unilocular lipid droplets and few mitochondria, and their main function is to store energy. In humans, WAT is mainly found in visceral adipose tissue and abdominal subcutaneous adipose tissue; b. Beige adipocytes contain moderate amounts of lipid droplets and mitochondria, which can express UCP1 thermogenesis, but it’s reversible; c. Brown adipocytes contain multilocular lipid droplets and many mitochondria expressing UCP1, which can burn fat and produces heat. BAT is mainly found in the interscapular and subclavian.