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

Submit a comment

Metabolism of C-peptide in the dog. In vivo demonstration of the absence of hepatic extraction.
K Polonsky, … , H Tager, A H Rubenstein
K Polonsky, … , H Tager, A H Rubenstein
Published September 1, 1983
Citation Information: J Clin Invest. 1983;72(3):1114-1123. https://doi.org/10.1172/JCI111036.
View: Text | PDF
Research Article

Metabolism of C-peptide in the dog. In vivo demonstration of the absence of hepatic extraction.

  • Text
  • PDF
Abstract

The in vivo hepatic metabolism of connecting peptide (C-peptide) in relation to that of insulin has not been adequately characterized. A radioimmunoassay for dog C-peptide was therefore developed and its metabolism studied in conscious mongrel dogs, with sampling catheters chronically implanted in their portal and hepatic veins and femoral artery. The hepatic extraction of endogenous C-peptide under basal conditions was negligible (4.3 +/- 4.5%) and was similar to the hepatic extraction of C-peptide measured during the constant exogenous infusion of C-peptide isolated from dog pancreas. Simultaneously measured hepatic extraction of endogenous and exogenously infused insulin were 43.8 +/- 7.6 and 47.5 +/- 4.4%, respectively. The metabolic clearance rate of infused C-peptide was 11.5 +/- 0.8 ml/kg per min and was constant over the concentration range usually encountered under physiological conditions. In additional experiments, the effect of parenteral glucose administration on the hepatic extraction of C-peptide and insulin was investigated. The hepatic extraction of C-peptide (6.2 +/- 4.0%) was again negligible in comparison with that of insulin (46.7 +/- 3.4%). Parenteral glucose administration did not affect the hepatic extraction of either peptide irrespective of whether it was infused peripherally, intraportally, or together with an intraportal infusion of gastrointestinal inhibitory polypeptide. The fasting C-peptide insulin molar ratio in both the portal vein (1.2 +/- 0.1) and femoral artery (2.1 +/- 0.3) was also unaffected by the glucose stimulus. These results therefore indicate that, since the hepatic extraction of C-peptide is negligible and its clearance kinetics linear, the peripheral C-peptide concentration should accurately reflect the rate of insulin secretion. New approaches to the quantitation of hepatic extraction and secretion of insulin by noninvasive techniques are now feasible.

Authors

K Polonsky, J Jaspan, W Pugh, D Cohen, M Schneider, T Schwartz, A R Moossa, H Tager, A H Rubenstein

×

Guidelines

The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.

  • Comments appear on the Journal’s website and are linked from the original article’s web page.
  • Authors are notified by email if their comments are posted.
  • The Journal reserves the right to edit comments for length and clarity.
  • No appeals will be considered.
  • Comments are not indexed in PubMed.

Specific requirements

  • Maximum length, 400 words
  • Entered as plain text or HTML
  • Author’s name and email address, to be posted with the comment
  • Declaration of all potential conflicts of interest (even if these are not ultimately posted); see the Journal’s conflict-of-interest policy
  • Comments may not include figures
This field is required
This field is required
This field is required
This field is required
This field is required
This field is required
Rich Text Editor, eletter_body
Editor toolbarsClipboard/Undo CutKeyboard shortcut Ctrl+X CopyKeyboard shortcut Ctrl+C PasteKeyboard shortcut Ctrl+V Paste as plain textKeyboard shortcut Ctrl+Alt+Shift+V Paste from Word UndoKeyboard shortcut Ctrl+Z RedoKeyboard shortcut Ctrl+YEditing Find Replace Select All Spell Check As You TypeLinks LinkKeyboard shortcut Ctrl+K Unlink AnchorForms Form Checkbox Radio Button Text Field Textarea Selection Field Button Image Button Hidden FieldTools Maximize Show BlocksDocument Source Save New Page Preview Print TemplatesBasic Styles BoldKeyboard shortcut Ctrl+B ItalicKeyboard shortcut Ctrl+I UnderlineKeyboard shortcut Ctrl+U Strikethrough Subscript Superscript Copy FormattingKeyboard shortcut Ctrl+Shift+C Remove FormatParagraph Insert/Remove Numbered List Insert/Remove Bulleted List Decrease Indent Increase Indent Block Quote Create Div Container Align Left Center Align Right Justify Text direction from left to right Text direction from right to left Set languageStylesStylesStylesFormatFormatFontFontSizeSizeColors Text Color Background Color
Press ALT 0 for help
◢Elements path 

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

Sign up for email alerts