Selenium and glutathione peroxidase levels in cystic fibrosis.

Whole blood selenium and glutathione peroxidase levels were measured in 20 infants and children (aged 6 months to 15 years) with cystic fibrosis. The whole blood selenium concentration in cystic fibrosis was 0.122 +/- 0.025 microgram/gm. Although the levels of selenium in cystic fibrosis children were below the levels found in a study of healthy children (0.223 +/- 0.007 microgram/gm), they are comparable to those found in children with phenylketonuria treated dietetically and exceed the blood selenium level of healthy children in New Zealand. Levels of the selenoenzyme glutathione peroxidase in children with cystic fibrosis (0.042 +/- 0.007 units/mg Hb) were in the normal range (0.035 +/- 0.003 units/mg of Hb). These results do not support the hypothesis that deficiency of selenium is reponsible for cystic fibrosis.