| Effects of
Exercise on Muscle Metabolites and Sarcoplasmic
Reticulum Function in Ovariectomized Rats
I.
GIGLI 1,2, L. E. BUSSMANN1
1Institute of
Biology and Experimental Medicine - CONICET, 2Department
of Medicine, Faculty of Veterinary Sciences,
University of Buenos Aires, Buenos Aires,
Argentina
Received May 14, 2001
Accepted August 16, 2001
Summary
The relationships between exercise and
metabolites as well as between exercise and
sarcoplasmic reticulum function were studied in
gastrocnemius muscle of ovariectomized-trained
rats. Prolonged moderate-intensity exercise,
treadmill up-hill run for 90 min with a 10°
incline, decreased the muscle glycogen content.
Exercise until exhaustion further lowered the
glycogen concentration to 13 % of the control,
together with a significant decrease of ATP and
glucose-6-phosphate concentrations. Also,
Ag+-induced Ca2+release, measured in whole muscle
homogenate, showed a 30 % reduction on
exhaustion, while Ca2+ uptake was unaffected by
this exercise. ATPase activities, of both
homogenate and SR vesicles, and Ca2+ transport in
the latter preparation were not altered on
exhaustion. It could be concluded from these
results that muscular fatigue in ovariectomized
rats after aerobic exercise is caused by the
change in energy supply and Ca2+ release from the
SR, this latter possibly due to metabolites
generated by the exercise.
Key
words
Exercise
· Sarcoplasmic reticulum · Muscle fatigue ·
Rats
Reprint
requests
L. E. Bussmann, Instituto de Biologia y Medicina
Experimental-CONICET. Vuelta de Obligado 2490,
Buenos Aires (1428), Argentina, Fax: +54 11
4786-2564, e-mail address: bussmann@dna.uba.ar
|
