Expression of sulphonylurea receptor protein in mouse kidney

The sulphonylurea receptor (SUR) is the site of action for sulphonylurea de rivatives such as glibenclamide, which are widely used as oral hypoglycaemi c agents. Sulphonylureas have also been shown to affect urine flow and salt excretion by the kidney; therefore, the use of these drugs may have import ant implications for the pharmacological manipulation of renal salt handlin g. The purpose of the present investigation was to increase our understandi ng of the possible role of SUR in the regulation of renal function by deter mining the distribution of SUR isoforms within mouse kidney. Immunostaining with anti-SUR antisera revealed specific staining of SUR2B in distal nephr on segments of mouse kidney. A diffuse, low level staining was observed in proximal tubules in the inner cortical region. No evidence was found for th e presence of SUR2B in intra-renal blood vessels. Reverse-transcription pol ymerase chain reaction and Western blotting experiments indicated that SUR2 B is the only known isoform expressed. These data demonstrate that SUR2B in mouse kidney is expressed in tubule regions that are critical in determini ng renal salt excretion.