Defective ENaC Processing and Function in Tissue Kallikrein-deficient Mice

摘要: An inverse relationship exists between urinary tissue kallikrein (TK) excretion and blood pressure in humans rodents. In the kidney TK is synthesized large amounts connecting tubule mainly released into fluid where its function remains unknown. present study mice with no functional gene coding for (TK-/-) were used to test whether enzyme regulates apically expressed sodium transporters. Semiquantitative immunoblotting of renal cortex revealed an absence 70-kDa form gamma-ENaC TK-/- mice. Urinary Na+ after amiloride injection was blunted mice, consistent reduced ENaC activity. Amiloride-sensitive transepithelial potential difference colon, also expressed, decreased whereas amiloride-sensitive alveolar clearance lung, not unchanged. lacking B2 receptor kinins, abundance increased, indicating that kinin-mediated. Incubation membrane proteins from resulted appearance band gamma-ENaC, able promote cleavage vitro. Finally, mouse cortical collecting ducts isolated microperfused vitro, addition luminal increased significantly intracellular concentration, activation entry cation. The results demonstrate TK, like several other proteases, can activate colon.