Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
  • Clinical Research and Public Health
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • Conversations with Giants in Medicine
    • Video Abstracts
  • Reviews
    • View all reviews ...
    • Complement Biology and Therapeutics (May 2025)
    • Evolving insights into MASLD and MASH pathogenesis and treatment (Apr 2025)
    • Microbiome in Health and Disease (Feb 2025)
    • Substance Use Disorders (Oct 2024)
    • Clonal Hematopoiesis (Oct 2024)
    • Sex Differences in Medicine (Sep 2024)
    • Vascular Malformations (Apr 2024)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Clinical Research and Public Health
    • Research Letters
    • Letters to the Editor
    • Editorials
    • Commentaries
    • Editor's notes
    • Reviews
    • Viewpoints
    • 100th anniversary
    • Top read articles

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • Conversations with Giants in Medicine
  • Video Abstracts
  • In-Press Preview
  • Clinical Research and Public Health
  • Research Letters
  • Letters to the Editor
  • Editorials
  • Commentaries
  • Editor's notes
  • Reviews
  • Viewpoints
  • 100th anniversary
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Publication alerts by email
  • Advertising
  • Job board
  • Contact
Top
  • View PDF
  • Download citation information
  • Send a comment
  • Terms of use
  • Standard abbreviations
  • Need help? Email the journal
  • Top
  • Abstract
  • Version history
  • Article usage
  • Citations to this article

Advertisement

Research Article Free access | 10.1172/JCI106382

The role of pH, PCO2, and bicarbonate in regulating rat diaphragm citrate content

Sheldon Adler

1Department of Medicine, Montefiore Hospital and University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213

Find articles by Adler, S. in: JCI | PubMed | Google Scholar

Published September 1, 1970 - More info

Published in Volume 49, Issue 9 on September 1, 1970
J Clin Invest. 1970;49(9):1647–1655. https://doi.org/10.1172/JCI106382.
© 1970 The American Society for Clinical Investigation
Published September 1, 1970 - Version history
View PDF
Abstract

Intact rat diaphragms were exposed in vitro to varying CO2 tensions and bicarbonate concentrations, and the steady-state citrate content of diaphragm muscle was measured to investigate the relationship between metabolism and extracellular pH, PCO2, and (HCO3-). In addition, rat hemidiaphragms were incubated with 1,5-citrate-14C under different acid-base conditions, and 14CO2 production was determined as a measure of citrate oxidation.

Acidification of the bathing medium achieved by raising CO2 tension or lowering (HCO3-) was associated with a decrease in muscle citrate content. On the other hand, alkalinization of the medium induced by lowering CO2 tension or raising (HCO3-) caused tissue citrate content to rise. At a physiologic extracellular pH value of approximately 7.40, citrate content was decreased or normal depending on the CO2/HCO3- combination employed to attain the pH. Under low bicarbonate and low PCO2 conditions, citrate content was reduced. A similar result was found at external pH values of 7.15, implying that at these two extracellular pH levels (HCO3-) primarily determines citrate content. When changes in citrate content were compared with intracellular pH data reported earlier using the same intact diaphragm preparation, no simple relation between citrate content and intracellular pH was found. The effect of acidity on citrate content seems related to a change in citrate oxidation since the latter increased progressively with increasing degrees of medium acidity.

These results show that cellular metabolism is not a simple function of extracellular pH but is dependent on the particular combination of PCO2 and bicarbonate employed to achieve the pH value. These studies also suggest that accumulation or disposal of organic acids, such as citric acid, helps to regulate cellular acidity thereby contributing to the cells' defense against external acid-base disorders.

Browse pages

Click on an image below to see the page. View PDF of the complete article

icon of scanned page 1647
page 1647
icon of scanned page 1648
page 1648
icon of scanned page 1649
page 1649
icon of scanned page 1650
page 1650
icon of scanned page 1651
page 1651
icon of scanned page 1652
page 1652
icon of scanned page 1653
page 1653
icon of scanned page 1654
page 1654
icon of scanned page 1655
page 1655
Version history
  • Version 1 (September 1, 1970): No description

Article tools

  • View PDF
  • Download citation information
  • Send a comment
  • Terms of use
  • Standard abbreviations
  • Need help? Email the journal

Metrics

  • Article usage
  • Citations to this article

Go to

  • Top
  • Abstract
  • Version history
Advertisement
Advertisement

Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts