Hyperuricemia in cystic fibrosis [letter].

Davidson et al report hyperuricemia in cystic fibrosis patients ingesting large quantities 
of pancreatic extracts. This article and others emphasize the considerable purine 
content of these preparations as causal to the increased serum and 
urine uric acid levels in patients who consume them. This may 
find clinical application, since uric acid production from RNA might be 
decreased by an inhibitor of ribonuclease. While itself a purine chain, 
polyadenylic acid added to pancreatic extracts may prevent the hydrolysis of 
mixed-base ribonucleic acid to uric acid precursors, while allowing the beneficial 
effects of the other pancreatic enzymes to prevail. - A number 
of weaknesses to the proposal bears stressing before we begin giving 
polyadenylic acid to our patients. No one knows whether nucleic acids 
are malabsorbed in cystic fibrosis. If polyadenylic acid produces only 70% 
inhibition of pancreatic ribonucleases at a one-to-one ratio of substrate and 
inhibitor, a relatively enormous amount of polyadenylic acid would have to 
be fed with the pancreatic extracts. If there were an intestinal 
enzyme capable of cleaving polyadenylic acid, the treatment would add to, 
not subtract from, the purine load. Finally, Stapleton et al's results 
suggest that more than 75% of the purine load in the 
pancreatic extracts would probably be absorbed anyway. 