Catecholamine metabolism in the patients with rheumatoid arthritis

The amount of urinary catecholamine of healthy subjects and patients with rheumatoid arthritis, particularly before and after synovectomy, was studied. (1) The urinary catecholamine of patients with rheumatoid arthritis showed a lower value than that of healthy subjects. The greater the amount of intraarticularly injected steroids was and the more severe the stage and class of rheumatoid arthritis were, the lower the level of adrenaline was and the more reduced the activity of phenylethanolamine-N-methyltransferase was. (2) The level of urinary noradrenaline in patients with rheumatoid arthritis was lower than that of healthy subjects, but there was no relationship between the level of noradrenaline and the amount of intraarticularly injected steroids. Considering that noradrenaline tended to approach to the normal level as the stage of class of rheumatoid arthritis was more severe, the level of urinary noradrenaline in patients with rheumatoid arthritis seems to reflect the existence of a certain compensatory system in the enzyme system of catecholamine metabolism rather than the influence of the adrenal cortex system. (3) The urinary catecholamine was decreased after synovectomy; especially, noradrenaline level was remarkably decreased. These results suggest that catecholamine plays an important role in the appearance of pain or other clinical signs in rheumatoid arthritis.