Hydrocortisone: a specific modulator of in vitro cell proliferation and aging

The effects of hydrocortisone on the proliferative activity of various vertebrate fibroblast-like cell lines have been measured. The proliferative activity of human fetal lung-derived cell lines, such as WI-38, and those of human fetal foreskin origin were always enhanced by the hormone. The addition of hydrocortisone to a number of other vertebrate cell lines grown under identical conditions showed growth inhibition. We also determined that the stimulation of WI-38 cell growth by hydrocortisone was a specific steroid-cell interaction by testing the growth promoting activity of several steroids with molecular structures similar to that of hydrocortisone. This observation was further supported by the presence of high effinity glucocorticoid binding sites in WI-38 cells whose concentration per cell was found to decrease with increased in vitro age. The results suggest that the proliferative response to hydrocortisone shows a cell-type specificity as well as a steroid-molecular structure specificity. The response appears to be mediated by high affinity glucocorticoid binding sites.