Increased calcium content in cultured fibroblasts from trisomy patients: comparison with cystic fibrosis fibroblasts.

The elemental composition of cultured fibroblasts from trisomy patients, cystic fibrosis patients, and from healthy controls was compared by means of electron probe X-ray microanalysis. Significantly higher relative Ca concentrations (relative to phosphorus) and higher Ca/K ratios, were found in both trisomy and CF fibroblasts. Significantly lower relative Na concentrations and lower Na/K ratios were only found in CF fibroblasts; the Na content of trisomy fibroblasts was normal. Challenge with prostaglandin E2 did not cause any further rise in cell calcium in trisomy fibroblasts, nor did it cause elevated calcium levels in the control. If the mechanism causing elevated calcium levels in trisomy fibroblasts is similar to that causing abnormally high levels of calcium in CF fibroblasts, it might be located at the membrane level. The analytical results are discussed in the light of the observation that cyclic AMP levels are abnormally inducible in CF and trisomy fibroblasts.