Renal excretion of vanillylmandelic acid and homovanillic acid in rats with paw edema or adjuvant arthritis.

1. Urinary excretion of unconjugated vanillylmandelic acid (VMA) and homovanillic acid (HVA) was found to be decreased in adjuvant arthritic rats. The decrease is apparently not due to impaired animal activity, but it could be explained by the reduction of catecholamine biosynthesis and/or release induced by E prostaglandins the biosynthesis of which is increased in the inflammation. It could also be caused by an increased "consumption" of catecholamines during prostaglandin biosynthesis. 2. Both the reduction of biosynthesis or release and an increased "consumption" of catecholamines would mean that inflammation is characterized by deficiency of the anti-inflammatory catecholamines. 3. The investigations failed to demonstrate an adequate decrease of the urinary excretion of VMA and HVA in rats with edemas induced by carrageenin, serotonin, formaline, silver nitrate, kaolin, dextran and baker's yeast, respectively. The experiments should be repeated with other catecholamine metabolites.