Reciprocal Expression of mRNA for Inhibin β_C and β_A Subunits in Hepatocytes

Abstract

Messenger RNA expression of activin β_C subunit in the liver was compared with that for β_A subunit before and after 70% hepatectomy. mRNA for β_C was abundantly expressed in the liver but decreased at 12h and later after 70% hepatectomy, whereas that for β_A was increased 12h after the hepatectomy. We also compared the expression of mRNA for β_A and β_C in cultured rat hepatocytes. mRNA for β_C subunit was abundantly expressed in the beginning of the culture but was reduced gradually after stimulation with epidermal growth factor. In contrast, mRNA for β_A subunit was undetectable before stimulation and was increased 24 to 48h after stimulation with the mitogen. These results indicate that expression of mRNA for β_C and β_A is regulated differently. The role of activin C may be different from that of activin A in the liver.