Electrical polarization of rectal mucosa and excretion of tetrahydroaldosterone in patients with cystic fibrosis of pancreas and in normal subjects.

The electrical potential difference (PD) across the rectal wall was measured in 
26 patients with cystic fibrosis of pancreas (CFP) and in 18 
healthy subjects. The PDs obtained in normal children were identical to 
those previously obtained in normal adults. A significantly greater dispersion of 
the values was observed in CFP. When the patients were divided 
into groups according to metachromasia in fibroblast cultures, the mean PD 
was increased only in the ametachromatic group. True enough, this observation 
suggests a difference between various forms of CFP, distinguished by metachromasia, 
and thus is a further indication of the heterogeneity of the 
disease. The greater abnormalities in metachromasia negative patients may, however, be 
due solely to the fact that these patients are more severely 
affected by the disease. The urinary excretion of tetrahydroaldosterone in patients 
was within the ranges obtained in controls, which excludes the possibility 
of secondary hyperaldosteronism as the source of increased PD. No evidence 
was provided in favour of a basic defect in the intestinal 
transport of Na+ or Cl minus, but K+ concentrations in faecal 
fluids of patients were significantly lower than in controls. The equilibrium 
concentration of K+ could be accounted for by simple passive diffusion, 
suggesting that the epithelium behaved inertly with respect to this ion 
in CFP. 