Intravesicular NAD has no effect on sodium-dependent phosphate transport in isolated renal brush border membrane vesicles

The effects of intravesicular NAD on Na+-dependent32Pi uptake were investigated in isolated rat kidney brush border membrane vesicles (BBMV). NAD was introduced into the vesicles by osmotic shock, and extravesicular NAD was removed by passing the vesicles through a anion exchange column. The effectiveness of the osmotic shock procedure and the hydrolysis of extra- and intravesicular NAD were controlled by enzymatic analysis and thin layer chromatography. ADP-ribosylation of the membrane proteins was analyzed in vesicles osmotically shocked in the presence of either [adenylate-32P]-NAD or [adenine-2,8-3H]-NAD by SDS-polyacrylamide gel electrophoresis.