The renal tubules secrete h+ into the tubular fluid, where most of it binds to bicarbonate, ammonia, and phosphate buffers.

The renal control of pH buffering involves neutralizing more acid or base more than other systems in the body because they can also expel them from the body. The renal tubule secretes H+ into tubular fluid, where most of it binds to bicarbonate, ammonia, and phosphate buffers in renal tubules. Therefore the bound and free H+ excreted is excreted in urine. Other body systems only reduce the concentration by binding it to chemical buffers.