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2. Grip strength and biochemical measurements, i.e. serum creatine phosphokinase (CPK) activity and creatine urinary excretion rate, together with histological studies, were performed in resting animals during a period of 14 days of PYR administration in a dose producing 20-30% whole blood acetylcholinesterase inhibition. No evidence was found of a deleterious effect of this treatment on the skeletal muscle.
3. In contrast, following physical exercise, the same treat ment significantly exacerbated the biochemical changes reflecting a loss of integrity in skeletal muscles, namely, increased CPK and urinary creatine excretion rate. The significance of this observation remains to be clarified.
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