SYNCHRONOUS INCREASE OF 4 ACUTE PHASE PROTEINS SYNTHESIZED BY THE SAME HEPATOCYTES DURING THE INFLAMMATORY REACTION - A COMBINED BIOCHEMICAL AND MORPHOLOGIC KINETICS STUDY IN THE RAT

  • 1 January 1981
    • journal article
    • research article
    • Vol. 44  (2) , 105-115
Abstract
The hepatic synthesis of 4 acute phase reactants (APR), i.e., fibrinogen, .alpha.1-acid glycoprotein, .alpha.2-macroglobulin and haptoglobin was investigated in rats suffering from turpentine-induced inflammation. To follow the change in the rates of synthesis of the 4 APR, their concentrations were measured by immunonephelemetry in the plasma and the hepatic microsomal fraction at various times after injury. A synchronous increase in the concentrations of these 4 proteins was observed in the liver (maximum 24 h) and in the plasma (maximum 40 h) of the same animals. The site of their synthesis was localized in liver sections by light microscopy and EM using direct immunoperoxidase labeling. Of the liver cells, only the hepatocytes were labeled. In the early period of the inflammatory reaction (10-16 h) synthesizing cells were detected principally in the periportal zone, but 24 h later the labeled area was extended to nearly the entire hepatic lobule. When serial sections of liver were examined at that time the same cells were contained simultaneously the 4 APR. Within the cells examined by EM the 4 proteins were localized in the secretory pathway, i.e., rough and smooth endoplasmic reticulum, Golgi apparatus and secretory vacuoles. The experimental inflammatory reaction evidently induces a synchronous increase in the synthesis of 4 APR by the liver; this increased synthesis apparently results from an increased number of synthesizing hepatocytes; these cells have a preferential periportal localization and individual hepatocytes are not specialized in the synthesis of a single plasma protein.