Abstract
1. Muscle biopsies were taken from patients with rheumatoid arthritis (RA) and analyzed for ATP, ADP, AMP, phosphorylcreatine (PC), creatine (Cr), and a number of glycolytic intermediates. The results were compared with corresponding values from normal healthy subjects and from a group of patients with connective tissue diseases other than RA. 2. The only consistent finding was a significant lower level of ATP in the RA patients as compared to that of the other two groups. The interrelationship of ATP to the total adenine nucleotide (TA) content, however, was normal. The extent of the decrease in ATP appeared to be related to the duration of the disease and possibly also to the severity of the disease.