Brief dietary restriction increases skeletal muscle glucose transport in old Fischer 344 rats

DJ Dean, GD Cartee - The Journals of Gerontology Series A …, 1996 - academic.oup.com
DJ Dean, GD Cartee
The Journals of Gerontology Series A: Biological Sciences and …, 1996academic.oup.com
The primary purpose of this study was to determine the impact of brief dietary restriction (DR;
5 or 20 days) on skeletal muscle glucose transport activity (GTA) oj'24-month-old female
Fischer 344 rats. Basal GTA of isolated epitrochlearis muscles was unaffected by DR. Insulin-
stimulated GTA was significantly increased by DR only at 20 days (+ 51+). We also
assessed the influence of DR on energy sources (blood-borne and stored). An∼-20+
decline in glycemia occurred in each DR group, but plasma-free fatty acid and β …
Abstract
The primary purpose of this study was to determine the impact of brief dietary restriction (DR; 5 or 20 days) on skeletal muscle glucose transport activity (GTA) oj'24-month-old female Fischer 344 rats. Basal GTA of isolated epitrochlearis muscles was unaffected by DR. Insulin-stimulated GTA was significantly increased by DR only at 20 days ( + 51+). We also assessed the influence of DR on energy sources (blood-borne and stored). An ∼-20+ decline in glycemia occurred in each DR group, but plasma-free fatty acid and β-hydroxybutyrate concentrations were unaffected. Plasma insulin was reduced by 50+ after 20 days. Hepatic glycogen was rapidly mobilized (−69+ at 5 days; −83+ at 20 days). The depletion of visceral adipose stores was slower (no significant decline at 5 days; −30+ at 20 days), but the eventual reduction accounts for a significant amount of energy. The results demonstrate that muscle from old rats can rapidly upregulate GTA in response to brief DR. The relative magnitude of this increase represents a substantial portion of the increases previously observed after prolonged DR.
Oxford University Press