Role of renin-angiotensin system in adipose tissue dysfunction

Blockade of angiotensin II type 1 (AT(1)) receptor improves insulin sensitivity and diabetic condition. In short-term regulation, angiotensin II changes lipid metabolism and in long-term regulation, it affects insulin sensitivity and adipocyte differentiation in adipose tissue. These effects are mainly mediated by AT(1) receptor. AT(1) receptor blocker improves insulin sensitivity and induces adipocyte differentiation by increasing peroxisome proliferator-activated receptor-gamma (PPARgamma) and transcription factors in adipose tissue in diabetic and atherosclerotic models. Clinical studies indicate that AT(1) receptor blockers prevent the new onset of diabetes and improve insulin sensitivity. On the other hand, AT(2) receptor stimulation appears to cause antagonistic actions against AT(1) receptor signaling. Although further investigations are necessary on the AT(2) receptor function in adipose tissue, studies using AT(2) receptor agonists, in addition to those using AT(1) receptor blockers, would contribute to the treatment of metabolic syndrome and associated pathological disorders.