AJP - Gastrointestinal and Liver Physiology, Vol 265, Issue 1 1-G8, Copyright © 1993 by American Physiological Society

ARTICLES

Regulation of hepatic Na(+)-HCO3- cotransport and pH by membrane potential difference

J. G. Fitz, S. D. Lidofsky and B. F. Scharschmidt
Duke University Medical Center, Durham, North Carolina 27710.

Hepatocytes possess several mechanisms for membrane acid-base transport, which work in concert to maintain intracellular pH (pHi) in a narrow physiological range, despite metabolic processes that produce and consume substantial quantities of H+ and HCO3-.Na(+)-H+ and Cl(-)-HCO3- exchangers contribute to recovery from intracellular acidosis and alkalosis, respectively, but are largely inoperative at physiological values of pHi. Recent studies indicate that hepatocytes also possess a mechanism for coupled transport of Na+ and HCO3- across the basolateral membrane. This appears to be the dominant pathway for membrane acid-base transport operative under basal conditions, mediates influx of Na+ and HCO3-, and is an important contributor to recovery from intracellular acidosis. In this review, the properties of hepatic Na(+)-HCO3- cotransport are described with emphasis on its effects on pHi and Na+ homeostasis and on the possible role of membrane potential difference as a signal modulating the rate of HCO3- influx and pHi of hepatocytes through effects on this transporter.

This article has been cited by other articles:

				N. Abuladze, A. Pushkin, S. Tatishchev, D. Newman, P. Sassani, and I. Kurtz Expression and localization of rat NBC4c in liver and renal uroepithelium Am J Physiol Cell Physiol, September 1, 2004; 287(3): C781 - C789. [Abstract] [Full Text] [PDF]

				L. V. Virkki, D. A. Wilson, R. D. Vaughan-Jones, and W. F. Boron Functional characterization of human NBC4 as an electrogenic Na+-HCO3- cotransporter (NBCe2) Am J Physiol Cell Physiol, June 1, 2002; 282(6): C1278 - C1289. [Abstract] [Full Text] [PDF]