| Popis: |
The proliferative capacity of Syrian hamster dermal fibroblasts has been previously shown to be inversely related to the age of the donor (Mech. Ageing and Dev., 34 (1986) 151). The present study demonstrates an inverse correlation between in vivo age and the in vitro morphological and proliferative response of Syrian hamster dermal fibroblasts to the tumor promoter phorbol-12,13-didecanoate. Treatment of fetal fibroblasts with promoter increased the proliferative life span of the cultures by approximately 2-fold, but did not increase the frequency of conversion to established cell lines. Neonatal and young adult fibroblasts exhibited intermediate responses to promoter treatment, showing 54.9% and 33.1% extension, respectively. In contrast, promoter treatment had no significant effect on aged adult fibroblasts. Maximal extension required continual treatment beginning in primary culture or at passage 1. Promoter-induced extension of proliferative life span appears to be mediated through the prolonged maintenance of small, highly proliferative cells that are present in primary cultures of these cells. |
