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


     

Am J Physiol Endocrinol Metab 256: E668-E675, 1989;
0193-1849/89 $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 Wajngot, A.
Right arrow Articles by Landau, B. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wajngot, A.
Right arrow Articles by Landau, B. R.

AJP - Endocrinology and Metabolism, Vol 256, Issue 5 E668-E675, Copyright © 1989 by American Physiological Society

ARTICLES

Testing of the assumptions made in estimating the extent of futile cycling

A. Wajngot, V. Chandramouli, W. C. Schumann, K. Kumaran, S. Efendic and B. R. Landau
Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.

In estimating glucose and fructose 6-phosphate futile cycling in vivo, complete detritiation of [2-3H]glucose is assumed at the glucose 6-phosphate level, [3-3H]glucose at triose phosphate formation, and [6-3H]glucose in its conversion to glucose via pyruvate. [3-3H]glucose detritiation via the pentose cycle is assumed to be negligible. Normal and non-insulin-dependent diabetic subjects, in the basal state and infused with glucose, were given [2-3H,2-14C]galactose, and 3H-to-14C ratios in blood glucose were determined. [2-3H,2-14C]glucose was given with acetaminophen, and 3H/14C in urinary glucuronide was determined. Detritiation at glucose 6-phosphate was approximately 80%. [3-3H,1-14C]fructose was infused, and 3H/14C was determined in blood glucose and urinary glucuronide. At triose phosphate, 75-90% of the 3H was removed. The pentose cycle contribution was only a few percent. [6-3H,6-14C]glucose was infused, and 3H/14C in blood lactate was determined. [3-3H,3-14C]lactate was infused, and ratios in blood glucose were determined. Maximally, 10% of 3H from [6-3H]glucose was retained. If glucose and galactose are metabolized in the same hepatic site(s), glucose conversion to three-carbon intermediates in the indirect pathway of glycogen formation occurs in extrahepatic tissue(s). Reported estimates of futile cycling, although qualitatively correct, quantitatively require correction.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Endocrinol. Metab.Home page
K. F. Petersen, M. Krssak, V. Navarro, V. Chandramouli, R. Hundal, W. C. Schumann, B. R. Landau, and G. I. Shulman
Contributions of net hepatic glycogenolysis and gluconeogenesis to glucose production in cirrhosis
Am J Physiol Endocrinol Metab, March 1, 1999; 276(3): E529 - E535.
[Abstract] [Full Text] [PDF]


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