Opposite responses of nuclear spermidine N8-acetyltransferase and histone acetyltransferase activities to regenerative stimuli in rat liver
Article first published online: 5 DEC 2005
Copyright © 1992 American Association for the Study of Liver Diseases
Volume 15, Issue 5, pages 928–933, May 1992
How to Cite
Desiderio, M. A. (1992), Opposite responses of nuclear spermidine N8-acetyltransferase and histone acetyltransferase activities to regenerative stimuli in rat liver. Hepatology, 15: 928–933. doi: 10.1002/hep.1840150529
- Issue published online: 5 DEC 2005
- Article first published online: 5 DEC 2005
- Manuscript Accepted: 2 JAN 1992
- Manuscript Received: 2 AUG 1991
- Ministero Universita Ricerco Scientifica Tecnologica, Rome, Italy
Experiments performed in different models of hepatic regeneration at the time of maximal DNA synthesis, determined by thymidine kinase activity assay, demonstrated that spermidine N8-acetyltransferase activity increased 48 hr after CCl4 administration (2-fold), 72 hr after CCl4 plus phenobarbital (3-fold) and 24 hr after partial hepatectomy (4.5-fold). On the contrary, at these times histone acetyltransferase activity diminished (approximately twofold) and was unchanged compared with control values in the liver of hepatotoxin-treated and hepatectomized rats, respectively. Histone acetylation was, however, enhanced 1.5-fold before the onset of DNA replication (14 hr), and 3.4-fold after the peak of DNA synthesis (32 hr) in the liver of hepatectomized rats.
α-Difluoromethylornithine, a specific and irreversible inhibitor of ornithine decarboxylase that was administered to hepatectomized rats, blocked polyamine synthesis, thymidine kinase activity and consequently liver regeneration 24 hr after the surgery. In those conditions, spermidine N8-acetyltransferase activity was decreased approximately twofold, whereas histone acetyltransferase activity was elevated approximately twofold. All these effects were reversed by putrescine coadministration.
Altogether, these findings showed that nuclear spermidine N8-acetyltransferase and histone acetyltransferase activities were regulated in opposite ways during the processes associated with liver regeneration. Moreover, they suggested that the polyamines themselves might have a direct or indirect role in this regulation. (HEPATOLOGY 1992;15:928–933).