Insulin iontophoresis in cystic fibrosis.

Insulin and its vehicle without insulin were administered separately by iontophoresis to 
patients with cystic fibrosis (CF), obligate heterozygotes, and healthy controls. The 
resultant sweat chloride concentration after treatment with both preparations was compared 
in each individual. No difference after the two treatments was found 
in the control sample. A decrease in sweat chloride concentration after 
insulin iontophoresis in comparison with the vehicle was observed in both 
the CF (P smaller than 0.005) and heterozygote (P smaller than 
0.01) samples. These observations suggest an involvement of insulin in CF 
and a possible role of insulin in sweat gland function. 