Exercise training and the glucose transport system in obese shhf/
mcc-facp rats.
Ferrara, Cynthia M., W. Michael Sherman, Nicole Leenders, Sylvia A.
McCune, Karla Roehrig.
Sport and Exercise Science, School of Physical Activity & Human
Services, and Department of Food Science and Nutrition, The Ohio
State University, Columbus, OH 43210
APStracts 3:0273A, 1996.
The effects of a similar exercise training stimulus on maximal
insulin-stimulated (MIS) plasma membrane glucose transporter number
and glucose transport were determined in lean and obese SHHF/Mcc-facp
rats. Six-week-old lean and obese male rats were randomly divided
into 4 groups: lean sedentary (LSED), obese sedentary (OSED), lean
exercise (LEX), and obese exercise (OEX). An 8-12 wk treadmill
running program equalized daily muscular work for LEX and OEX. Plasma
membranes were isolated from control and MIS muscles of mixed fiber
types. MIS significantly increased glucose transport 3.4- and 2.8
-fold in LSED and OSED. MIS significantly increased glucose
transporter number 2.5-fold in LSED, but there was no increase in
glucose transporter number in OSED. VO2peak and citrate synthase
activity were increased a similar amount for LEX and OEX
demonstrating a similar training stimulus. MIS significantly and
similarly increased glucose transport in LEX and OEX (4.4- and 5.1
-fold, respectively). The effects of MIS on plasma membrane glucose
transporter number in the exercise-trained rats were similar to the
responses observed in the sedentary lean and obese groups. MIS
significantly increased glucose transporter number 2.6-fold in LEX,
whereas there was no increase in glucose transporter number in OEX.
The reduction in MIS glucose transport in OSED appears to be related
to a defect in the processes associated with the translocation of
glucose transporters to the plasma membrane. Exercise training of the
obese rats apparently did not alter this defect. Similar increases in
VO2peak, citrate synthase, and MIS glucose transport in LEX and OEX
suggest that insulin resistance does not limit the ability of the
glucose transport system to adapt to exercise training in the obese,
male, SHHF/Mcc-facp rats.
Received 10 October 1995; accepted in final form 5 June 1996.
APS Manuscript Number A1091-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96