Kallikrein does not modify the transepithelial potential of rat renal distal convoluted tubules

The addition of kallikrein to the luminal solution of rabbit urinary bladder has been demonstrated to degrade amiloride-sensitive sodium channels in a time- and concentration-dependent manner. The aim of this study was to determine whether kallikrein has a similar effect on the amiloride-sensitive sodium channels present in the luminal membrane of the perfused rat distal convoluted tubule in vivo. The transepithelial potential (measured using conventional microelectrodes) was -11.9 +/- 2.2 mV [n = 10] and decreased to +0.4 +/- 0.7 mV [n = 10] in the presence of 5 mumol/l luminal amiloride. A 17-min perfusion of the tubular lumen with 100 units/l of porcine glandular kallikrein did not significantly alter the control transepithelial potential nor the change in potential elicited by amiloride. Similarly, the transepithelial potential was not altered by the perfusion of 100 nmol/l bradykinin.