Ribosomal RNA activity and protein in skeletal muscles of chronic ethanol-fed rats

The effect of prolonged ethanol exposure on ribosomal RNA activity and the content of RNA and protein in skeletal muscles of 15- and 22-25-month-old rats was evaluated. Experimental rats were fed a liquid diet containing 6.7% ethanol for 2, 4 and 6 months, and control rats were pair-fed an isocaloric diet. The in vivo incorporation of [3H]puromycin into nascent peptides on messenger RNA-ribosome complexes was determined to assess muscle ribosomal RNA activity. This activity was significantly reduced in extensor digitorum longus and soleus muscles of rats fed ethanol for 2 months. While the total RNA content of these muscles was unchanged after feeding ethanol for 2, 4 and 6 months, their messenger RNA content was decreased from 26-34%. The total protein content was reduced after ethanol was consumed for 6 months. Taken together, the results suggest that alterations in the transcriptional or posttranscriptional control of messenger RNA may contribute toward the development of alcoholic myopathy after prolonged ethanol consumption.