Differentiation is not restored in hybrids between independent variants of a rat hepatoma.

Crosses have been undertaken between cells of three independent clones of dedifferentiated rat hepatoma variants to investigate whether "complementation" leading to restoration of the original differentiation would occur. Hybrids were examined between ten days and two months after fusion for the presence of intracellular albumin and for their ability to proliferate in glucose-free medium where survival requires activity of the liver-specific gluconeogenic enzymes. In none of the three possible crosses involving the three variants was evidence of reexpression of hepatic functions obtained.