Biological Synthesis of a Growth Factor for Mammalian Cells in Tissue Culture.

Abstract

A non-dialyzable substance was recovered in crude form from growth fluid of mouse lung fibroblasts adapted to a serum-free medium. This substance was capable of replacing the serum protein normally required for human liver cell growth. The substance in the material from mouse lung cell growth fluid is heat labile. The crude material was heat coagulable with loss of growth promoting activity for human liver cells. A graded dose response of growth of liver cells was obtained.