AJP - Renal Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Renal Physiol 245: F622-F633, 1983;
0363-6127/83 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chan, Y. L.
Right arrow Articles by Giebisch, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chan, Y. L.
Right arrow Articles by Giebisch, G.

AJP - Renal Physiology, Vol 245, Issue 5 622-F633, Copyright © 1983 by American Physiological Society

ARTICLES

Passive driving forces of proximal tubular fluid and bicarbonate transport: gradient dependence of H+ secretion

Y. L. Chan, G. Malnic and G. Giebisch

The effect of oncotic pressure changes on fluid (Jv) and net bicarbonate transport (JHCO-3) and the transepithelial bicarbonate permeability (PHCO-3) were measured by an improved luminal and capillary microperfusion method that allows paired experiments on the same tubule. Rat proximal tubules were pump-perfused and Jv and [HCO-3] measured with [14C]inulin and a pH glass electrode. Raising peritubular protein (0-8-15 g/100 ml bovine serum albumin) stimulated Jv and HCO-3 reabsorption. The response to oncotic pressure changes was asymmetrical since changes of the luminal protein concentration had no significant effects. Whereas transepithelial solvent drag effects on HCO-3 must be minimal, peritubular protein most likely stimulates translocation of fluid and bicarbonate from intercellular spaces into peritubular capillaries. PHCO-3 was measured from HCO-3 net flux along a lumen-to-capillary-directed electrochemical potential gradient. In these experiments active H+ transport and Jv were minimized by 10(-4) M acetazolamide and luminal raffinose. PHCO-3 was 1.77 X 10(-5) cm X s-1 and was unaffected by increasing luminal flow rate from 10 to 45 nl X min-1. Since bicarbonate backflux is only a small fraction of physiological rates of JHCO-3, net transport alterations at varying [HCO-3] in the lumen must be due to changes in active HCO-3 (H+) transport. Thus, active H+ ion secretion across the luminal membrane of the proximal tubule is gradient dependent.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Renal Physiol.Home page
Z. Du, Q. Yan, Y. Duan, S. Weinbaum, A. M. Weinstein, and T. Wang
Axial flow modulates proximal tubule NHE3 and H-ATPase activities by changing microvillus bending moments
Am J Physiol Renal Physiol, February 1, 2006; 290(2): F289 - F296.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
T. Wang
Role of iNOS and eNOS in modulating proximal tubule transport and acid-base balance
Am J Physiol Renal Physiol, October 1, 2002; 283(4): F658 - F662.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
H. Chang and T. Fujita
A numerical model of acid-base transport in rat distal tubule
Am J Physiol Renal Physiol, August 1, 2001; 281(2): F222 - F243.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
R. Unwin, R. Stidwell, S. Taylor, and G. Capasso
The effects of respiratory alkalosis and acidosis on net bicarbonate flux along the rat loop of Henle in vivo
Am J Physiol Renal Physiol, November 1, 1997; 273(5): F698 - F705.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online