Lysosomal enzyme secretion by cystic fibrosis fibroblasts is normal

Lysosomal enzyme secretion by skin fibroblasts derived from cystic fibrosis homozygotes and normal donors of the same range of age, sex and culture passage number were compared. No differences were detected between these groups in their rates of spontaneous lysosomal enzyme release. Incubation of either normal or cystic fibrosis fibroblasts with cystic fibrosis serum did not alter these secretion rates. The lysosomal enzyme secretion of both normal and cystic fibrosis fibroblasts responded similarly to incubation with NH₄Cl, monensin, A23187, trifluoperazine or Cytochalasin B. It was concluded that lysosomal enzyme hypersecretion, which has previously been suggested to occur in cystic fibrosis, is unlikely to provide a reliable diagnostic test for the disease.