Action of angiotensin receptor subtypes on the renal tubules and vasculature: Implications for volume homeostasis and atherosclerosis

Angiotensin-II (ANG-II) is a potent endocrine and paracrine hormone that functions in humans through two distinct G-protein-coupled transmembrane receptor subtypes (AT-1 and AT-2). ANG-IT is found in nearly all tissues of the body including the brain, heart, kidneys, gonads, and gastrointestinal tract. Just as it is found in nearly every organ system of the body, so is it involved in an array of physiologic processes from fetal development to blood pressure control. ANG-II regulates blood pressure by controlling sodium reabsorption in the proximal tubule, altering the glomerular filtration rate and renal blood flow, and by modifying the production and release of aldosterone in the adrenal gland. Additionally, ANG-II is involved in several pathologic processes including the development of hypertension, cardiomyopathy, atherosclerosis, and diabetic nephropathy. It is able to exert influences in these widely varying processes by working together with multiple different second messenger systems including the MAP kinase pathway, nitric oxide production, and phospholipase C and D, and several arachidonic acid metabolites. This paper is a review of the current knowledge of ANG-II and its receptors in health and disease.