Levels of messenger ribonucleic acids for plasma proteins in rat liver during acute experimental inflammation.

The levels of mRNA for plasma proteins and for metallothionein in rat liver during the acute-phase response were studied by hybridization to specific cDNA probes. The mRNA for alpha 2-macroglobulin, the beta-chain of fibrinogen, alpha 1-acid glycoprotein (so-called acute-phase reactants) reached a maximum level between 18 and 36 h after inducing an acute inflammation. The level of mRNA for metallothionein-I peaked earlier, after 12 h. The mRNA for transferrin showed a delayed increase with a broad maximum for its relative level after 36-60 h. The mRNA levels for albumin and alpha 2u-globulin (so-called negative acute-phase reactants) decreased, reaching a minimum of 25% of the normal level after 36 h (albumin) and after 72 h (alpha 2u-globulin). The ratios of the rates of incorporation of leucine into the proteins over the levels of their mRNA in liver changed only a little, indicating that the rates of synthesis of plasma proteins in the liver are regulated at the mRNA level during the acute-phase response to inflammation.