Abstract
The influence of training and anabolic steroids (methandrostenolone) on the enzyme
activity of the LDH system was investigated in 72 male guinea pigs. Sedentary animals
and animals subjected to two different training regimens with and without anabolic
steroids were compared in six groups each consisting of 12 guinea pigs. The training
was performed on a rodent treadmill for 1 month, 30min/day at an inclination of 45°
or 5°, and at a speed of 30m/min. Total LDH, its isozymes, and the composition of
M and H subunits were determined enzymatically and by electrophoretical separation
on cellulose acetate membrane in the following muscle fiber types: m. vastus lateralis
white (FG) and red portion (FOG), m. soleus (SO), m. psoas major white (FG) and red
portion (FOG), and in the left ventricle of the heart. The administration of anabolic
steroids did not change the activity of total LDH or the composition of M and H subunits
in sedentary animals. Exercise at 5° inclination significantly reduced the total LDH
and the concentration of H subunits in FOG, SO, and heart muscle fibers but not in
FG muscle fibers. The additional application of anabolic steroids intensified these
changes and also reduced the total LDH and the H subunit in FG as well as the M subunit
in FOG, SO, and heart muscle fibers. After exercise at 45° inclination with and without
the application of anabolic steroids, the activity of LDH and its isozymes was identical
to the values obtained in untrained animals but significantly higher than after the
training at 5° inclination. The typing of FG, FOG, and SO muscle fibers by the LDH
isozyme pattern was not satisfactory, especially for the discrimination between FOG
and SO fibers but also between FG and FOG fibers of muscles with different anatomic
functions both in sedentary and trained animals.
Key words
LDH isozymes - H and M subunits - different training forms - anabolic steroids - skeletal
and heart muscle fibers
