Inhibition of ouabain-sensitive ATPase by the saliva of patients with cystic fibrosis of the pancreas.

A study has been made of the effect of saliva from children 
with cystic fibrosis of the pancreas (CFP) on various components of 
the ATP hydrolyzing enzyme system. The ouabain-sensitive ATPase activity of erythrocyte 
membranes prepared from intact erythrocytes preincubated with CFP saliva was 35 
+/- 4 nmol Pi/mg fry wt membrane suspension/hr, compared with 48 
+/- 7 nmol Pi/mg dry wt membrane suspension/hr when the erythrocytes 
were preincubated with control saliva. A calcium-activated component of ATPase was 
decreased from 202 +/- 30 nmol Pi/mg dry wt membrane suspension/hr 
in erythrocytes preincubated with control saliva, to 151 +/- 17 nmol 
Pi/mg dry wt membrane suspension/hr when the incubation was carried out 
with CFP saliva. In a second series of experiments, ultrafiltered saliva 
was added directly to an ATPase assay. The saliva from children 
with CFP brought about a mean decrease in ouabain-sensitive ATPase of 
16% compared with control saliva. 