The effect of tobacco smoke condensate on the growth and longevity of human diploid fibroblasts.

Human embryonic diploid lung fibroblasts were exposed to various fractions of cigarette smoke condensate over their in vitro life-time. Most fractions were toxic at a concentration of 50 microgram/ml, with the exception of the strong acid and one water soluble basic fraction, which stimulated growth and increased longevity significantly at this concentration. Most fractions produced no effect on cell growth at 10 microgram/ml, with the exception of another basic fraction which inhibited growth at 1 microgram/ml. Nicotine had no apparent effect on growth and longevity at 50 microgram/ml. The neutral fraction containing the polynuclear hydrocarbon carcinogens produced normal growth and longevity at 10 microgram/ml. No cell transformations were observed.