Recent clinical studies have shown that treatment with angiotensin II type 1 (AT1) receptor blockers or angiotensin-converting enzyme (ACE) inhibitors protects against the development of insulin resistance in hypertensive patients and new onset of diabetes in “at-risk” patients, indicating that the renin-angiotensin system (RAS) especially tissue RAS may contribute to the regulation of glucose metabolism [1–4]. This evidence concerns the gene ACE and diabetes mellitus.