Influence of gamma-irradiation on liver regeneration in normal and starved rats.

The liver region of rats was submitted to a radiation dose of 1430 r and, following hepatectomy, a study was made of the effect of irradiation during early stages of regeneration on cellular division and, following 72 hr, on the overall values of liver weight and contents of DNA, RNA, and protein. Irradiation was found to retard the appearance of mitosis in regenerating tissue and to result in a decreased rate of regeneration of DNA. Rats were starved for 24 hr, then irradiated as above and operated, following which they were normally fed. Under these conditions liver regeneration was more rapid; furthermore there was more pronounced retardation of the regeneration of various constituents under the influence of irradiation, which appeared to be linked with the greater variations in body weight between non-irradiated and irradiated animals. If only the head, or the limbs, were irradiated, there resulted a temporary retardation of mitosis in the operated liver, but this was of short duration and, following the period of inhibition, was succeeded by a period of intense division. (auth)