[Effect of infrared radiation on the kinetics of the guinea pig's epidermis cells. Comparison with UV radiation effect].

In vivo exposition of guinea pig epidermal cells to infra-red irradiation (IR) led to significant, biphasic reduction of the proliferating activity after 6 h and 72 h. Not before 168 h after exposure, the proliferating activity rose above the normal rate. The quantitative alterations of DNA-proliferating cells went along with prolongation of the S-phase and the cell cycle. UV-irradiated cells react earlier by reduction of the DNA-proliferating activity directly followed by stages of hyperproliferation.