We have developed the methodology for evaluating the effects of pathophysiological conditions on the molecular mechanisms of hepatic protein synthesis and fibrogenesis in baboons and man. Total RNA was extracted from percutaneous liver biopsies of five baboons who were chronically fed an ethanol-rich liquid diet, their pair-fed controls and from humans with a variety of liver abnormalities. Chronic alcohol administration in baboons with liver fibrosis and normal serum albumin levels increased in vitro protein synthesis as measured by [35S]methionine incorporation, albumin mRNA content and Type I procollagen mRNA content. There was no difference in the β-actin (a constitutive protein) mRNA content. In humans, serum albumin levels correlated with albumin mRNA content as indicated by the intensity of dot blot hybridization and Type I procollagen mRNA levels correlated with the activity of liver fibrosis. The use of RNA-DNA hybridization to investigate procollagen mRNA from human biopsies appears to be a valuable tool for evaluating the potential for collagen synthesis and the future course of liver disease. Besides the use of RNA-DNA hybridization, we describe other methodologies which are useful in delineating the levels of gene expression responsible for hepatic mRNA regulation in normal liver and disease states in man. The use of molecular techniques to evaluate human liver disease provides an opportunity to develop clinically relevant information while at the same time offering the additional advantage of providing fundamental knowledge about fibrogenesis.