AJP - GI AJP: Gastrointestinal and Liver Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Gastrointest Liver Physiol 251: G695-G700, 1986;
0193-1857/86 $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 Favus, M. J.
Right arrow Articles by Coe, F. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Favus, M. J.
Right arrow Articles by Coe, F. L.

AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 5 695-G700, Copyright © 1986 by American Physiological Society

ARTICLES

Effects of medium pH on duodenal and ileal calcium active transport in the rat

M. J. Favus, D. A. Bushinsky and F. L. Coe

To study the effect of pH on Ca active transport in vitro pH was varied from 7.1 to 7.7, and bidirectional transmural Ca fluxes were measured under short-circuited conditions across duodenum or ileum from rats fed either normal chow (NCD, 1.2% Ca) or low Ca (LCD, 0.002% Ca). Duodenum and ileum from rats fed LCD actively absorbed calcium at medium pH 7.4. Reduction in mucosal and serosal medium bicarbonate from 25 to 10 mM (pH 7.4 to 7.1) decreased duodenal net Ca absorption (Jnet) from 121 +/- 32 to 39 +/- 9 nmol X cm-2 X h-1 (P less than 0.02) and ileal Jnet from 74 +/- 13 to 22 +/- 6 (P less than 0.01). The decline in duodenal and ileal Ca Jnet was due to a decrease in the mucosal-to-serosal flux (Jm----s). Raising medium pH from 7.4 to 7.7 by increasing bicarbonate from 25 to 50 mM did not alter Ca Jm----s, serosal-to-mucosal flux (Js----m), or Jnet X Ca fluxes across ileum from rats fed NCD demonstrated net secretion. LCD ileal Jm----s was unaltered when pH was reduced from 7.4 to 7.1 by increasing the PCO2 content of the buffer from 30 to 81 mmHg while maintaining bicarbonate at 24 mM. The results indicate that in vitro conditions that simulate metabolic acidosis (low bicarbonate and pH, normal PCO2) inhibit 1,25D-mediate calcium Jm----s, whereas conditions that simulate respiratory acidosis have no effect on Ca fluxes. The present studies suggest that decreases in calcium Jm----s is by a primary alteration in transport of other ions rather than direct effect on Ca transport.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
N. Charoenphandhu, K. Tudpor, N. Pulsook, and N. Krishnamra
Chronic metabolic acidosis stimulated transcellular and solvent drag-induced calcium transport in the duodenum of female rats
Am J Physiol Gastrointest Liver Physiol, September 1, 2006; 291(3): G446 - G455.
[Abstract] [Full Text] [PDF]


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