Regulation of plasma acute-phase protein and albumin levels in the liver of scalded rats

Abstract

At 12 h after scalding of rats a doubling of the hepatocyte nuclear DNA content, which arose from the presence of additional complete genomes and not from amplification of genes coding for the major acute-phase proteins or albumin, was observed. Examination of relative transcription rates per control DNA mass revealed that alpha 1-acid-glycoprotein and cysteine-proteinase-inhibitor genes remained constitutive, alpha- and gamma-fibrinogen and haptoglobin genes underwent transcriptional activation for 290 and 339% respectively, whereas the relative transcription rate of albumin decreased to 65% of the control level. Along with these changes, the alpha 1-acid glycoprotein, cysteine-proteinase inhibitor and the fibrinogen mRNA concentrations increased about 500%, haptoglobin mRNA 250%, whereas the albumin mRNA concentration fell to 86% of the control. The regulation of the mRNA levels was assessed by comparing the relative change in transcription rates expressed per control DNA content with the relative changes of mRNA concentrations. We arrived at the conclusion that the concentrations of alpha 1-acid-glycoprotein and cysteine-proteinase-inhibitor mRNAs were predominantly regulated by a post-transcriptional mechanism, albumin mRNA by a transcriptional mechanism, and the fibrinogen and haptoglobin mRNAs by a combination of both. The degree of change of the serum levels of the examined proteins was similar to that of their mRNA concentrations and was the result of the complete use of the available RNA templates in protein synthesis.