Renin-angiotensin-aldosterone system in insulin resistance and metabolic syndrome.

Obesity and its consequent complications such as hypertension and metabolic syndrome are increasing in incidence in almost all countries. Insulin resistance is common in obesity. Renin- angiotensin system (RAS) is an important target in the treatment of hypertension and drugs that act on RAS improve insulin resistance and decrease the incidence of type 2 diabetes mellitus, explaining the close association between hypertension and type 2 diabetes mellitus. RAS influences food intake by modulating the hypothalamic expression of neuropeptide Y and orexins via AMPK dephosphorylation. Estrogen reduces appetite by its action on the brain in a way similar to leptin, an anorexigenic action that seems to be mediated via hypothalamic pro-opiomelanocortin (POMC) neurons in the arcuate nucleus and synaptic plasticity in the arcuate nucleus similar to leptin. Estrogen stimulates lipoxin A4, a potent vasodilator and platelet anti-aggregator. Since both RAS and estrogen act on the hypothalamic neuropeptides and regulate food intake and obesity, it is likely that RAS modulates LXA4 synthesis. Thus, it is proposed that Angiotensin-II receptor blockers and angiotensin-converting enzymes and angiotensin-II antagonists may have the ability to augment LXA4 synthesis and thus bring about their beneficial actions.