Effect of the nucleotides CMP and UMP on exhaustion in exercise rats

ABSTRACT

The aetiology of muscle fatigue has yet not been clearly established. Administrationof two nucleotides, cytosine monophosphate (CMP) and uridine monophosphate(UMP), has been prescribed for the treatment of neuromuscular affections inhumans. Patients treated with CMP/UMP recover from altered neurological functionsand experience pain relief, thus the interest to investigate the possible effect ofthe drug on exhausting exercise. With such aim, we have determined, in exercised ratstreated with CMP/UMP, exercise endurance, levels of lactate, glucose and glycogen,and the activity of several metabolic enzymes such as, creatine kinase (CK), lactatedehydrogenase (LDH), and aspartate aminotransferase (AST). Our results show thatrats treated with CMP/UMP are able to endure longer periods of exercise (treadmillrun).Before exercise, muscle glucose level is significantly higher in treated rats, suggestingthat the administration of CMP/UMP favours the entry of glucose in themuscle. Liver glycogen levels remains unaltered during exercise, suggesting thatCMP/UMP may be implicated in maintaining the level of hepatic glycogen constantduring exercise. Lactate dehydrogenase and aspartate aminotransferase activity is significantlylower in the liver of treated rats. These results suggest that administrationof CMP/UMP enable rats to endure exercise by altering some metabolic parameters (AU)

RESUMEN

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