| Abstract: | Hydrocortisone is a modulator of cell division and has been shown to prolong the replicative in vitro life span of human embryonic lung fibroblasts. Time lapse cinematography was used to analyze the proliferative behavior of individual cells in populations of fibroblasts exposed to hydrocortisone in young cultures during a single growth cycle and in aged cultures that had been continuously exposed to hydrocortisone. Results indicate that hydrocortisone causes a decrease in the interdivision time (IDT) of a portion of the cells in the population and this effect is augmented after continuous exposure to hydrocortisone. Hydrocortisone does not appear to increase the number of initial dividers in the population but increases growth rate in the early stages of the culture period. Analysis of mother-daughter IDT pairs further suggests that hydrocortisone exerts its effects on IDT independently for a given cell. |
