Immunolocalization of AQP1, 5 and 9. Immunohistochemical staining of AQP1 in paraffin-embedded sections of the uterus from pigs. Anti-AQP1 antibody labels capillary endothelium of the uterus (A-F). Immunoperoxidase labeling of AQP1 from the pig kidney cortex (positive control) (S). The labeling is seen in both of the apical cell membrane and in the basolateral cell membrane in proximal tubule cells. AQP5 antibody stains luminal and glandular epithelial cells (arrows) and smooth muscle cells (G-L). The anti-AQP5 labels apical membrane of type I pulmonary epithelial cells of the pig (positive control) (U). AQP9 labels luminal and glandular epithelial cells of the uterus (arrows) (M-R). Immunoperoxidase labeling of AQP9 from the pig liver (positive control) (X). No staining was observed with using non-immune immunoglobulins (negative controls) (T, W and Y). L, lumen; CV, central vein; T, trophoblast. Bar = 50 μm.