Cyclic nucleotides in joint fluid in rheumatoid arthritis and in Reiter's syndrome

Levels of cyclic adenosine 3',5'-monophosphate (cAMP) and cyclic guanosine 3',5'-monophosphate (cGMP) have been investigated in joint fluid in inflammatory arthropathies. A disturbed balance between cAMP and cGMP due to a depressed level of cAMP was found in rheumatoid arthritis (RA) and Reiter's syndrome, in comparison with patients with osteoarthritis. No correlation could be demonstrated between the absolute levels of cAMP or cGMP and the degree of local inflammatory activity, white cell count, or lysosomal enzyme activity in the joint fluid. Intra-articular injection of epinephrine showed just as good an effect on local pain as betamethasone (Cellestona), but the steriod reduced the swelling more effectively. An increase in intracellular levels of cAMP at 20 min was observed following injection of epinephrine with a slight change in cGMP. Intra-articular injection of dibutyryl-cAMP (db-cAMP) produced a marked easing of local pain and swelling in each of the 4 patients so treated. It is concluded that stimulation of the beta-adrenergic system or injection with db-cAMP may be beneficial in rheumatoid inflammation.