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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Activins, Adipocytes, Animals, Cells, Cultured, Collagen, DNA, Fibroblasts, Inhibins, Liver, Liver Cirrhosis, Experimental, Male, RNA, Messenger, Rats, Rats, Sprague-Dawley, Transforming Growth Factor beta.
user
Is expression of activin A increased in cirrhotic and fibrotic rat livers? Context: Activin A, a member of the transforming growth factor (TGF)-beta superfamily, recently has been reported to suppress DNA synthesis and to induce apoptosis of hepatocytes. These biological functions are similar to those of TGF-beta1, which is overexpressed in liver cirrhosis. The aim of this study was to examine whether activin A is involved in liver cirrhosis and fibrosis. Liver cirrhosis or fibrosis was induced by intraperitoneal injections of dimethylnitrosamine or porcine serum into rats. The kinetics of activin A messenger RNA (mRNA) expression in cirrhotic and fibrotic livers and primary cultured rat hepatocytes were assessed by Northern blotting, and the localization of activin A was determined immunohistochemically. Modulation of type 1 collagen mRNA expression by activin A in rat cultured Ito/fat-storing cells and fibroblasts was also examined. Northern blotting showed that activin A mRNA expression was enhanced in fibrotic livers. The numbers of hepatocytes expressing immunoreactive activin A were significantly greater, especially around the fibrotic areas. Activin A mRNA expression in cultured hepatocytes was increased significantly by TGF-beta1 and by activin A itself. Furthermore, type 1 collagen mRNA expression in cultured cells was enhanced by activin A and TGF-beta1 in a synergistic manner.
assistant
Activin A is overexpressed in rat cirrhotic and fibrotic livers and may contribute to hepatic fibrogenesis. Final Decision: yes