Calmodulin quantitation in cystic fibrosis

Calmodulin (CaM) has been measured by radioimmunoassay in whole blood dried on filter paper from 7 patients with cystic fibrosis, 8 obligate heterozygotes and 9 presumably normal individuals. The mean concentration of CaM in the homozygote and the heterozygote group was 0.208 ± 0.009 and 0.219 ± 0.014 ng CaM/μg cell protein, respectively, while the concentration in the normal group was 0.152 ± 0.016 ng CaM/μg cell protein. A statistically significant difference in the mean calmodulin concentration was found between patients in the homozygote and heterozygote pool and the control group (p<0.005) but not between the homozygote and heterozygote groups. A quantitative and/or qualitative abnormality in CaM may contribute to the altered calcium metabolism observed in cystic fibrosis.