Antithrombin III (AT III), heparin cofactor has been known to be one of the important
protease inhibitors on the regulatory mechanism of coagulation and fibrinolysis, but
the site of synthesis of plasma AT HI has not yet been conclusively established, although
some observations suggested that the major site of AT III production may be the liver
and AT III levels in plasma is known to be decreased on the hepatic disorders. This
paper reports the deposition of the AT III specific fluorescence in the hepatocytes
of rat liver by immunofluorescent examination. Plasma AT III was purified by heparin
sepharose affinity chromatography and gel filtrations. Rabbit was immunized with this
purified AT III and Freund’s complete adjuvant and rabbit anti rat AT III serum was
obtained. This antiserum was comfirmed to be monospecific to rat AT HI by means of
immunoelectrophoresis. Freshly isolated rat liver was prepared as specimen and fixed
in acid alcohol and processed to dehydration and embedding into paraffin in conventional
way. Indirect immunofluorescent technique with FITC labeled anti rabbit gamma-globulin
were utilized for immunofluorescent staining and histological observation was performed
under Nikon FL fluorescent microscope. The localization of fluorescence was observed
in the hepatocytes which scattered in the acinus structures. The fluorescence in the
cytoplasma of these hepatocytes was homogeneously stained. As far as the fluorescence
is concerned, the synthesis of AT III may be performed not synchronizing among hepatocytes.
This immunofluorescent study supports the reported data of hepatic perfusion.
