[Skeletal muscle lactate dehydrogenase isoenzymes in rats after space flight and in hypokinesia].

Carbohydrate metabolism of soleus (red) and plantaris (mixed) muscles of rats exposed to space flight and hypokinesia were studied on a comparative basis. The red and mixed muscles responded in a different way to the exposures, as followed from the changes of the isoenzymic spectrum of LDH. The soleus muscle showed the greatest changes in the LDH spectrum on the 15th hypokinetic day. The changes were similar to those found in the soleus muscle of flight rats. The plantaris muscle showed the most marked changes on the 60th hypokinetic day. Alterations in the LDH spectrum of the plantaris muscle were not found in flight or control rats. The findings indicate the major contribution of changes in carbohydrate metabolism to atrophic and dystrophic developments in skeletal muscles under functional load.