The anatomical distribution of receptors for angiotensin II (Ang II) and atrial natriuretic peptide (ANP) within the kidney has been investigated by in vitro autoradiography. Ang II and ANP receptor binding occurs together in several sites in the kidney, including renal vasculature, glomeruli, proximal convoluted tubule of the outer cortex, and the vasa recta bundles of the inner stripe of the outer medulla. However, in the glomeruli, Ang II receptor binding occurs predominantly in mesangial cells, while ANP receptors are localized mainly to the visceral epithelial cells. In the inner medulla, there is a moderate density of ANP receptors in marked contrast with Ang II binding which is not detected in this site. Both Ang II and ANP receptors are modulated by alterations in sodium and fluid intake, and the peptides themselves. The overlapping distribution of receptors for these two peptide hormones in several intrarenal sites may provide an anatomical basis for their physiological interaction to regulate renal hemodynamics and tubular reabsorption of sodium and water.
- angiotensin II
- atrial natriuretic peptide