Serum AFP concentrations in normal adult BALB/c/J and in normal adult C3H/He mice were in the order of 0.6 µg/ml and 0.1 µg/ml, respectively. In BALB mice, AFP was localized in the cytoplasm of differeniated mono- and binucleated hepatocytes in centrolobular and intermediate zones of normal adult liver. No cellular AFP could be detected in liver sections of normal adult C3H mice.
CCl4 intoxication was accompanied by increase of serum AFP levels. A maximum was reached on day 4. Afterwards, concentrations declined. In sera of BALB/c/J mice, AFP levels reached values 10-fold higher and more than in sera of C3H/He mice. From day one after CCl4 intoxication, cellular AFP was detected in hepatocytes of portal and periportal areas including intermediate zones adjacent to the necrosis. The intensity of AFP staining reached a maximum between the days 3 and 4. Hepatocytes in front of the necrotic areas usually contained the strongest AFP reactions. In both mouse strains, cellular AFP pattern was comparable, but strongest immunoreactivity was observed in liver sections of BALB/c/J mice.
Liver injury and subsequent regeneration occurred to the same extent in both studied strains. The much higher serum AFP levels and the stronger AFP immunolocalizations in BALB mice were thought not due to increased numbers of AFP producing and releasing cells during liver regeneration. Additional mechanisms must play a role in increased AFP synthesis per single cell. C3H/He was a low AFP-inducible and BALB/c/J was a high AFP-inducible mouse strain.