All hepatocytes are involved in the expression of the albumin gene in the normal adult rat: a demonstration by in situ hybridization and immunoperoxidase techniques.

Immunoperoxidase techniques have yielded conflicting results concerning the percentage of hepatocytes engaged in albumin production in normal adult rats. In addition, the question of whether functional differences in the synthesis of plasma proteins exist within the hepatic lobule remains to be determined. To clarify these questions, we have searched for gene albumin transcripts by in situ hybridization, and for the corresponding protein by immunoperoxidase, on adjacent liver sections. We observed that all hepatocytes contain albumin transcripts as well as the albumin protein, without any detectable zonal variation within the liver lobule. Taken altogether, these results demonstrate that every hepatocyte, whatever its location in the hepatic lobule, is actively engaged in albumin gene expression.