Ornithine decarboxylase activity and polyamines in relation to aging of human fibroblasts

A reduction of ornithine decarboxylase (ODC) activity is associated with the decreased growth rate in early senescence of human embryonic lung fibroblasts. Inhibition of ODC activity with α-methyl ornithine in younger cells reduces cell proliferation; inhibition of putrescine deamination with aminoguanidine increases intracellular putrescine concentration and stimulates cell proliferation. The data suggests that the decreased cell proliferation which occurs in senescence may, at least in part, be dependent upon the reduced ODC activity.