[Relationship between the growth rate of the liver of young rats and the inhibitory effect of extracts of their liver on the multiplication of cultured cells].

We have shown that extracts of liver from young Rats are less active, than extracts of liver from adult Rats, in inhibiting the multiplication of cells in culture. This inhibitory activity is at a minimum in livers taken from 10 to 15 days old Rats, which corresponds to the time of maximum increase in weight of the liver. The existence of an inverse relationship between the inhibitory activity of these extracts and the state of proliferation of the liver suggests that the inhibitory substance contained in the liver extracts may act as a regulator of growth of the organ.