Imidazole dipeptides in experimental alcohol-induced myopathy

Rats were chronically fed a nutritionally complete liquid diet containing 35% of total calories as either ethanol, or (for the controls) an isocaloric amount of glucose. After 6 weeks of treatment, the feeding regime induced skeletal muscle myopathy as characterised by reductions in muscle weight and RNA content. Ethanol preferentially affected the metabolically glycolytic plantaris (Type II fibre-predominant) muscle of the rat, compared with the metabolically oxidative soleus (Type I fibre-predominant). The changes in the plantaris were associated with increases in the concentration (mumol per g wet weight) of anserine (18%) and carnosine (50%). No significant changes were seen for the concentrations of either anserine or carnosine in the soleus muscle. The total contents (mumol per muscle) of carnosine and anserine in the plantaris were not significantly altered by ethanol treatment, though a significant decrease in anserine content (30%) occurred in the soleus. It is concluded that reductions in imidazole dipeptide content, considered to be antioxidants and/or intracellular buffering agents, are not mediating factors in the development of chronic experimental myopathy.