Serum alpha-fetoprotein in rats after ligation of the common bile duct: relation to ductular cell (oval cell) proliferation.

Serum AFP levels were measured by radio-immunoassay in rats at various periods after ligation and section of the common bile duct and after sham-ligation. Transient elevations of serum AFP reaching statistically significant levels occurred at 3 to 10 days, 17 days and 28 days after ligation of the common bile duct but not in sham-operated rats. The peak elevations of serum AFP followed waves of mitosis in both the ductular cells and the hepatocytes as measured by autoradiography. Proliferation of hepatocytes, however, remained minor when compared to ductular cell multiplication. Ultra-structural and histochemical studies of the liver clearly distinguished ductular (oval) cells from hepatocytes and provided no evidence of transition from ductular cells to hepatocytes. Our findings suggest that ductular cell proliferation in the rat induced by ligation of the common bile duct may produce elevations in the serum AFP.