1. Enzymes, proteins, glycoproteins and lipids of rodent bile were compared with those of a plasma-membrane subfraction originating from the hepatocyte bile-canalicular membrane. 2. Three bile-canalicular glycoprotein enzyme activities were detected in bile. Comparison of the pH optimum and immunoinhibition properties of membrane and bile 5′-nucleotidase activity indicated that they were the same enzyme. Correspondence between membrane and bile alkaline phosphodiesterases also suggested that they were the same enzymes. Activities of Mg2+-stimulated adenosine triphosphatase, a lipid-dependent intrinsic membrane protein, and galactosyltransferase, a Golgi membrane marker, were not detected in bile. 3. Rodent bile contained 15 polypeptide bands that differed radically from those of bile-canalicular membranes. Bands that may correspond in molecular weight to liver plasma-membrane glycoproteins were present at low staining intensities in bile. A major protein of apparent molecular weight 49 500 was present, and albumin was detected by immunodiffusion. 4. The lipid composition of bile and bile-canalicular membrane also differed. Phosphatidylcholine accounted for 82% of rat bile phospholipids, and only trace amounts of phosphatidylinositol, phosphatidylserine and sphingomyelin were present. 5. The results indicate that in healthy animals, the bile-canalicular membrane is refractory to the action of bile acids during the secretory process. The presence of only small amounts of bile-canalicular membrane components, especially glycoprotein enzymes located at the outer face of the membrane, suggests that these are released from the membrane by bile acids after secretion of bile into the canalicular spaces.
Skip Nav Destination
Follow us on Twitter @Biochem_Journal
Article navigation
March 1976
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
March 15 1976
Role of membranes in bile formation. Comparison of the composition of bile and a liver bile-canalicular plasma-membrane subfraction
W H. Evans;
W H. Evans
1National Institute for Medical Research, Mill Hill, London NW7 1AA, U.K.
Search for other works by this author on:
T Kremmmer;
T Kremmmer
1National Institute for Medical Research, Mill Hill, London NW7 1AA, U.K.
Search for other works by this author on:
J G. Culvenor
J G. Culvenor
1National Institute for Medical Research, Mill Hill, London NW7 1AA, U.K.
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1976 London: The Biochemical Society
1976
Biochem J (1976) 154 (3): 589–595.
Citation
W H. Evans, T Kremmmer, J G. Culvenor; Role of membranes in bile formation. Comparison of the composition of bile and a liver bile-canalicular plasma-membrane subfraction. Biochem J 15 March 1976; 154 (3): 589–595. doi: https://doi.org/10.1042/bj1540589
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Follow us on Twitter @Biochem_Journal
Open Access for all
We offer compliant routes for all authors from 2025. With library support, there will be no author nor reader charges in 5 journals. Check here |
![]() View past webinars > |