Altered intracellular calcium in fibroblasts from patients with cystic fibrosis and heterozygotes.

The importance of intracellular calcium (Ca) in secretion and transmembrane ion movement 
led us to study Ca in cells from patients with cystic 
fibrosis (CF) which is a lethal genetic exocrinopathy. Skin fibroblasts from 
patients with CF, obligate heterozygotes (HZ), and age- and sex-matched controls 
(C) were used in matched pair experiments measuring 45Ca exchange into 
and efflux from the cells over time. CF cell lines and 
HZ cell lines exhibit increased 45Ca exchange when compared with their 
respective controls (P less than 0.005). The magnitude of this difference 
(approximately 30%) is not reduced when cells are washed with lanthanum 
chloride after the exchange period. This difference is likely attributable to 
an altered capacity of one or more of the intracellular Ca 
sequestering organelles. Further evidence for this explanation was seen in 45Ca 
efflux experiments in which CF cells retained a higher percent of 
their initial 0-time 45Ca than did C cells late in the 
efflux period (P less than 0.05). The finding of an altered 
Ca pool size in both CF and particularly HZ cells suggests 
that altered Ca metabolism is related to the basic gene defect 
in CF. 