Variations in regenerative growth of mouse liver following partial hepatectomy.

Liver regeneration after 35% or 70% hepatectomy of the mouse was studied. Significant variations in the pattern of regeneration were demonstrated within the same mouse strain, sex, age and under identical experimental conditions. In all the experiments there were large individual variations, and in some experiments significant differences between litters of the same age were seen. Liver DNA synthesis at 48 h after 35% hepatectomy in females, in experiments done at different times of the year, showed seasonal fluctuations, with high values in the winter and low values in the summer. The low values in the summer correlated with a shift of the DNA synthesis peak, which occurred later in the summer than in the winter.