Inhibition of Tamm-Horsfall glycoprotein induction of alkaline phosphatase in cystic fibrosis fibroblasts by medium conditioned by normal cells.

It is confirmed that the level of alkaline phosphatase in fibroblasts derived 
from cystic fibrosis patients can be induced many-fold by growing the 
cells in the presence of Tamm-Horsfall glycoprotein. It is further shown 
that normal fibroblasts produce a "CF corrective factor" which markedly inhibits 
this phenomenon. These observations support a previous hypothesis on the nature 
of the metabolic defect in cystic fibrosis. 