Journals of Gerontology Series A: Biological Sciences and Medical Sciences Large Type Edition
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
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 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
Google Scholar
Right arrow Articles by Ribeiro, R. T.
Right arrow Articles by Macedo, M. P.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ribeiro, R. T.
Right arrow Articles by Macedo, M. P.
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 63:560-565 (2008)
© 2008 The Gerontological Society of America

Loss of Postprandial Insulin Sensitization During Aging

Rogério Tavares Ribeiro, Ricardo Alexandre Afonso, Maria Pedro Guarino and Maria Paula Macedo

1 Departments of Physiology and 2 Biochemistry, Faculty of Medical Sciences, New University of Lisbon, Portugal.
3 Portuguese Diabetes Association, Lisbon, Portugal.

Address correspondence to M. Paula Macedo, PhD, Department of Physiology, Faculty of Medical Sciences, New University of Lisbon, Campo Mártires da Pátria, 130, 1169-056 Lisbon, Portugal. E-mail: mpmacedo.biot{at}fcm.unl.pt

With aging, there is a decrease in parasympathetic nervous activity. Since the hepatic parasympathetic nerves (HPNs) are essential to the disposal of nutrients, through the hepatic insulin sensitizing substance (HISS), we tested the hypothesis that aging leads to a lowering of postprandial glucose disposal by a decrease of the HISS-dependent component of insulin action. Insulin sensitivity was quantified in fed or fasted, male and female Wistar rats (from 6 to 52 weeks), using a euglycemic clamp. The HISS-dependent component was quantified by administration of the muscarinic antagonist atropine. Total insulin action decreased gradually up to 52 weeks of age: The HISS-independent component of insulin action decreased until 9 weeks of age and remained unchanged thereafter; the HISS-dependent component decreased from 9 weeks of age throughout aging. The continuous decrease of HISS action, uncovered by blocking the HPN, is the key phenomenon for the gradual decrease of insulin sensitivity with aging.

Key Words: Insulin resistance • Hepatic parasympathetic nerves • Hepatic insulin sensitizing substance • Type 2 diabetes mellitus






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
All GSA journals The Gerontologist
Journals of Gerontology Series B: Psychological Sciences and Social Sciences
Copyright © 2008 by The Gerontological Society of America.