Novel Aspects on Insulin Resistance

Insulin resistance occurs in several abnormalities, including the metabolic syndrome, with tissue-specific consequences. The main tissues of insulin's action are skeletal muscle, liver, and fat. Other organs, such as the central nervous system, are also affected. Insulin acts through its receptor and promotes the insulin signaling cascade. In insulin resistance, the metabolic pathway starting with phosphorylation of insulin receptor substrates is blunted. This results predominantly in reduced glucose uptake. Fat compounds are regarded as crucial in inducing insulin resistance (adipotoxicity). Because insulin resistance is involved in vascular disease, its appearance is now linked to the cardiometabolic syndrome. In insulin resistance, several circulating (endocrine) proteins are altered. These include leptin, adiponectin, resistin, and retinol binding protein, as well as ghrelin and obestatin, which can contribute to tissue lipid accumulation and changed satiety sensation. In conclusion, insulin resistance induces metabolic abnormalities, such as the cardiometabolic syndrome, caused by increased lipid availability, termed “adipotoxicity.” Measurement of insulin resistance might be helpful for identifying subjects prone to cardiometabolic disorders.