UII (A-F) and UT (G-L) proteins in the kidneys of 4-5-week-old WKY rats and SHRs. All images are representative and captured at x40 magnification (scale bar 50 µm). Images in the right hand column (C, F, I and L) represent typical negative control sections where primary antibody was omitted. UII-immunoreactivity in both the WKY rat (A) and the SHR (D) cortex was diffuse in distal (arrowheads) and proximal (black arrows) tubules, with no UII-immunoreactivity in glomeruli (red arrow, A). UII-immunoreactivity in both the WKY rat (B) and the SHR (E) medulla was located principally in the collecting ducts (arrowheads), with some immunoreactivity in the loops of Henle (arrows). In both the WKY rat (G) and the SHR (J) cortex UT-immunoreactivity was more intense in the distal (arrowheads) compared to proximal (black arrows) tubules, with UT-immunoreactivity absent in the SHR proximal tubules (black arrow, J); there was also some immunoreactivity in the glomeruli (red arrows). UT-immunoreactivity in both the WJY rat (H) and the SHR (K) medulla was localised to collecting ducts (arrowheads), with little immunoreactivity in the loops of Henle (arrows).