Partial hepatectomy (PHE) stimulates an intact part of the liver to exchange the existing «quiescence» program for the proliferative one. Several changes between 0.5 and 3 h after PHE are considered as manifestations of the abolishment of «quiescence» program: a temporal decrease of either UNA synthesis or accumulation of the newly formed RNA; a restricted variability of RNA transcripts; a partial retention of newly synthesized RNA within the nuclei thereby providing less RNA for the cytoplasm; previously obtained data about transient dissociation of ribosomes from endoplasmic reticulum. An involvement of the 2',5'-oligo(A)synthetase–RNAse L system in the process is suggested by up- and down-regulation of 2',5'-oligo(A)synthetase activity in the cytoplasm and in the nucleus, respectively, and by up-regulation of RNAse L content in regenerating liver. The production of IFN α/β, an inducer of the 2',5'-oligo(A)synthetase–RNAse L system, is also increased during transition period. A specific role of sinusoidal cells, the main producers of IFN α/β m the liver, in the abolishment of the old program is strongly suggested.