title: Acid-Base Homeostasis.
abstract: Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3(-) and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3(-) is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys.
authors.affiliation: Department of Medicine, Section of Nephrology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana; and Medicine Service, Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana Lhamm@tulane.edu.
authors.forename: L Lee
authors.initials: LL
authors.lastname: Hamm
authors.affiliation: Department of Medicine, Section of Nephrology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana; and Medicine Service, Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana.
authors.forename: Nazih
authors.initials: N
authors.lastname: Nakhoul
authors.affiliation: Department of Medicine, Section of Nephrology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana; and Medicine Service, Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Hering-Smith
mesh_terms: D000136:Acid-Base Equilibrium; D000137:Acid-Base Imbalance / Q000378:metabolism* / Q000503:physiopathology; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism* / Q000503:physiopathology; D008954:Models, Biological; D065667:Renal Elimination; D065608:Renal Reabsorption
chemical_list: D001639:Bicarbonates; D002245:Carbon Dioxide; D000641:Ammonia
keywords: acid-base equilibrium; acid-base homeostasis; acidosis; bone density; chronic; homeostasis; kidney; nephrolithiasis; pH regulation; renal insufficiency; renal physiology