The Effect of Intra-Muscular Injections of Alpha-tocopherol on the Activity of Phospho- Fructokinase in the Slow- and Fast-Twitch Skeletal Muscles of Metabolic Stress-Induced and Malnourished Rats

Abstract

It was been hypothesized that critical illness
will change the activity of phospho-fructokinase (PFK)
and that intramuscular (i.m) injections of the
antioxidant α-tocopherol would protect this ratelimiting
enzyme of glycolysis in the slow-twitch soleus
and in the fast-twitch extensor digitorum longus (EDL)
muscles of metabolically-stressed and malnourished
rats. Twenty eight male Wistar rats were divided into
four groups: controls (CNs), zymosan-injected (ZY), α-
tocopherol-injected (ZYE), and pair-fed (PF). Rats were
fed Osmolite-HN, and were sacrificed on day three. PFK
activity was measured in EDL and soleus muscles using
a fluorometric assay, and was found to be significantly
lower in both the soleus and EDL of ZY rats. The PFK
activity in the EDL of ZYE rats was comparable to the
PFK of PF rats and was significantly higher than ZY
rats on day three. Glycolysis in the slow- and fast-twitch
muscle of ZY rats is adversely affected, and three days
of i.m injections of α-tocopherol significantly (p<0.05)
protected PFK activity, in fast-twitch but not in slowtwitch
muscles.