RECIPROCAL EXPRESSION OF MESSENGER-RNA FOR INHIBIN BETA(C) AND BETA(A) SUBUNITS IN HEPATOCYTES

Messenger RNA expression of activin beta(C) subunit in the liver was c ompared with that for beta(A) subunit before and after 70% hepatectomy . mRNA for beta(C) was abundantly expressed in the liver but decreased at 12 h and later after 70% hepatectomy, whereas that for beta(A) was increased 12 h after the hepatectomy. We also compared the expression of mRNA for beta(A) and beta(C) in cultured rat hepatocytes. RNA for beta(C) subunit was abundantly expressed in the beginning of the cultu re but was reduced gradually after stimulation with epidermal growth f actor. In contrast, mRNA for beta(A) subunit was undetectable before s timulation and was increased 24 to 48 h after stimulation with the mit ogen. These results indicate that expression of mRNA for beta(C) and b eta(A) is regulated differently. The role of activin C may be differen t from that of activin A in the liver.