Putrescine stimulates growth of human bronchial epithelial cells in primary culture.

Explants of adult human bronchus were cultured in CMRL-1066 medium supplemented with heat-inactivated fetal bovine serum, hormones, antibiotics, and either 0.0, 0.1, 1, or 10 mM putrescine. The outgrowth of bronchial epithelial cells was stimulated in medium containing 1 mM putrescine, a concentration that partially inhibited the outgrowth of fibroblasts. In medium containing 10 mM putrescine, the outgrowth of epithelial cells was similar to that observed in the control medium, but the outgrowth of fibroblasts was completely inhibited for periods of at least 4 weeks. When 10 mM putrescine was added to cultures of bronchial fibroblasts, the fibroblasts were not killed. These results suggest that human bronchial epithelial cells have a higher requirement for putrescine for growth than fibroblasts, and the molecular basis for this observation is under investigation.