Inflammation-associated events in liver nuclei during acute-phase reaction.

Isolated liver nucleoli from rats undergoing turpentine-induced inflammation (acute-phase reaction) synthesize rRNA at a rate significantly higher than normal. This increase is associated with, and possibly preceded by, an enhanced methylation of RNA, which further increases when rRNA synthesis has reached a plateau level. Five hours after turpentine treatment, before clear activation of RNA synthesis and methylations, the nucleocytoplasmic transport of rRNA (largely 40S and 60S subunits) and the related ATPase activity of isolated nuclei are significantly increased. Apparently, posttranscriptional control is affected before transcription of rRNA during the onset of the acute-phase reaction: both kinds of events eventually contribute to the expansion of the ribosome population which occurs in the liver cells from rats undergoing an inflammatory process. All these processes are activated before the liver starts the synthesis of acute-phase proteins.