Adipokines are a group of over 600 bioactive molecules produced by adipose tissue that acts as paracrine and endocrine hormones. These molecules are important in the regulation of diverse processes including appetite control, fat distribution, inflammation, blood pressure, hemostasis and endothelial function. Adipokines may present anti and proinflammatory effects. Cardiovascular diseases (CVDs) can be one of the most important causes of death in diabetics and diabetes can in turn increase the risk of cardiovascular events. Obesity is a chronic condition. It is associated with overproduction of inflammatory adipokines by adipose tissue, which may link obesity to CVD and diabetes (Freitas Lima et al. 2015).

Adiponectin (ADIPOQ, also known as 30-kDa adipocyte complement-related protein ACRP30) is an adipocyte-derived hormone that acts as an antidiabetic and anti-atherogenic adipokine. ADIPOQ blood levels are decreased under conditions of obesity, insulin resistance and type 2 diabetes. ADIPOQ can form a wide range of multimers from trimers to high molecular weight (HMW) multimers (Waki et al. 2003). The trimeric form is shown here. Through binding adiponectin receptor proteins 1 and 2 (ADIPOR1 and 2), ADIPOQ trimer stimulates AMPK phosphorylation and activation in the liver and the skeletal muscle, enhancing glucose and fatty-acid utilisation. ADIPOR1 is abundantly expressed in skeletal muscle, whereas ADIPOR2 is predominantly expressed in the liver (Yamauchi et al. 2003). ADIPORs are thought to function as homo- or hetero-multimers. For simplicity, the combinations annotated here are shown as homodimers. Although ADIPOR1 and 2 are predicted to contain seven transmembrane domains, they are structurally, topologically and functionally distinct from GPCRs.