Abstract
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.