INS and metabolic syndrome: AMPK is a key regulator of cellular glucose and lipid metabolism, and its activation enhances insulin sensitivity in various tissues, promotes energy generation (glucose transport and fatty acid oxidation), inhibits energy expenditure (lipid synthesis, protein synthesis, and gluconeogenesis), inhibits the release of fatty acids, and promotes the fatty acid degradation in adipocytes, thus having the potential therapeutic effects on metabolic syndrome, diabetes, and so on (Daval et al., 2006).