alpha-Fetoprotein in toxic liver injury.

The temporal sequence of alpha-fetoprotein appearance in serum was determined in both necrogenic and nonnecrogenic liver injury. Ethionine, thioacetamide, and CCl4 were used to intoxicate male and female rats for evaluating serum enzyme levels, mitotic indices, and morphological reflections of impairment. Thioacetamide- and CCl4-induced cell death preceded the mitotic wave in residual hepatocytes, and, in the case of both agents, this intoxicant-mediated necrosis preceded the emergence of alpha-fetoprotein. Yet, although there was no evidence of either cell destruction or significant mitotic activity in ethionine-poisoned animals, serum alpha-fetoprotein levels progressively increased. Thus the temporal sequence of alpha-fetoprotein synthesis and/or release and cellular reorganization for regeneration suggests that reappearance of the protein macro-molecule is an expression of the altered phenotype observed during the "step-down" phase of liver regeneration.