|Figure 1||Figure 2||Figure 3||Figure 4|
Figure 1. Two families of enzymes (the receptor/guanylate cyclases, or rGCs, and the soluble guanylate cyclases, or sGCs) that are responsible for regulated synthesis of cyclic GMP.
|Figure 2. Immunocytochemical identification of uroguanylin-expressing epithelial cells in the small intestine (left), and in distal convoluted tubules (but not glomerular structures) in cortical region of the kidney (right). |
|Figure 3. Within the kidney, prouroguanylin is found in two types of distal tubule (the cortical collecting ducts and the distal convoluted tubules), but is not found in the proximal tubule or the glomerulus. (a) In this confocal image of rat kidney cortex, the tubules that comprise the proximal nephron are strongly autofluorescent (bright green), the tubules that comprise the distal nephron are weakly autofluorescent (faint green), and the glomeruli are non-fluorescent (unstained areas marked by asterisks). (b) Some weakly autofluorescent distal structures stain with an anti-aquaporin-2 antibody (red). These are the cortical collecting ducts (an example is highlighted by the white arrowhead). Other weakly autofluorescent distal structures do not stain with the anti-aquaporin-2 antibody. These are the distal convoluted tubules (an example is highlighted by the yellow arrowhead). (c) Profiles stained with an anti-prouroguanylin antibody (blue) correspond to both the cortical collecting ducts (e.g., white arrowhead) and the distal convoluted tubules (e.g., yellow arrowhead). (d) Merged image produced by superimposition of panels a - c.|
|Figure 4. Urinary sodium excretion (UNaV) evoked by intravascular infusion of atrial natriuretic peptide (ANP, red symbols) or uroguanylin (Ugn, green symbols)|