The integration of growth and the acute-phase response is investigated by comparing the mRNA levels in rat liver during acute inflammation with those after partial hepatectomy. Northern analysis is carried out for the mRNAs for thiostatin, alpha 2-macroglobulin, alpha 1-antitrypsin, inter-alpha-trypsin inhibitor subunit 1, haptoglobin, ceruloplasmin, transferrin, vitamin D-binding protein, alpha 1-acid glycoprotein, beta-fibrinogen, apolipoproteins A-IV and E, albumin, transthyretin, alpha 2-HS-glycoprotein, retinol-binding protein, beta-tubulin, c-myc protooncogene, glyceraldehyde-3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, ornithine transcarbamylase, and alcohol dehydrogenase. The acute-phase response dominates during the first 18 h. Changes in mRNA levels related to growth of the liver become important thereafter, and the capacity for an acute-phase response of plasma protein synthesis becomes greatly reduced. The early increase in the level of ceruloplasmin mRNA observed during inflammation is abolished during regeneration, and that of vitamin D-binding protein mRNA is converted into a decrease. The mRNAs levels of glyceraldehyde-3-phosphate dehydrogenase increase, and those for phosphoenolpyruvate carboxykinase decrease during regeneration. Ornithine transcarbamylase mRNA levels are found to exhibit negative acute-phase regulation. The pattern of transcriptional regulation is similar during inflammation and regeneration.