Distributional patterns of phospholipase C isozymes in rat kidney

As the first step to investigate the physiological function of phospholipase C (PLC), we determined the distribution patterns of PLC isozymes in normal rat kidneys using Western blotting analysis and immunohistochemistry. Western blotting analysis was performed in four regions (cortex, outer stripe and inner stripe of the outer medulla, and the inner medulla). PLC-beta 1 and beta 3 were detected in the inner stripe of the outer medulla and the inner medulla. PLC-gamma 1 was distributed homogeneously along the corticomedullary axis. PLC-gamma 2 was observed in the medulla and PLC-delta 1 showed a gradual increase from the cortex to the inner medulla, In contrast, no PLC-beta 4 was detected in all regions. On immunohistochemistry, the immunoreactivities to PLC antibodies were observed as follows: PLC-beta 1, from the thick ascending limb (TAL) to the inner medullary collecting tubule (IMCT); PLC-beta 3, in the glomerulus (Glm), the ascending thin limb (ATL) and the collecting tubule; PLC-beta 4, Glm, the proximal convoluted tubule (PCT), ATL, the distal convoluted tubule, the connecting tubule, and the collecting tubules; PLC-gamma 1, PCT, TAL and IMCT; PLC-delta 1, homogeneously from PCT to IMCT. PLC-beta 3 immunoreactivities were detected in the nuclei of the TAL, ATL, outer medullary collecting tubule (OMCT) and IMCT. PLC-beta 4 and gamma 2 were observed in Glm, MTAL, ATL, OMCT and IMCT. These results suggest the intrarenal site-specific existence of PLC isozymes that may regulate kidney functions through the PLC-mediated signal transductions.