The aim of our study was to evaluate the differences in protein and amino acid metabolism in the soleus (SOL) and the extensor digitorum longus muscle (EDL) after turpentine administration.Young rats were injected subcutaneously with turpentine oil (inflammation) or with saline solution (control).Twenty-four hours later muscles were dissected and incubated in modified Krebs-Heinseleit buffer to estimate total and myofibrillar proteolysis,chymotrypsin-like activity of proteasome (CHTLA),leucine oxidation,protein synthesis and amino acid release into the medium.The data obtained demonstrate that in intact rats,all parameters measured except protein synthesis are significantly higher in SOL than in EDL.In turpentine treated animals,CHTLA increaed and protein synthesis decreased significantly more in EDL.Release of leucine was inhibitied significantly more in SOL.We conclude that turpentine induced inflammation affects more CHTLA,protein synthesis and leucine release in EDL compared to SOL.