ABSTRACT
The human body fuelled by a typical western diet, rich in protein, generates about 1mmol of mineral acid per kg body weight each day. To maintain body alkali stores, the kidney must excrete an equivalent amount of acid each day (see Chapter 6). This excess nonvolatile acid is excreted by titrating filtered buffers (e.g., phosphates and creatinine) and by excreting ammonium (NH4
þ). Renal acid excretion can be inadequate as a result of either impaired NH4
þ and titratable acid excretion or inadequate HCO3 reabsorp-
tion. Both defects can develop as a result of impaired Hþ secretion along the renal tubules.
