Peculiarities of functioning of protein-synthesizing apparatus of the hibernator (Citellus undulatus).

Synthesis of proteins and RNA has been studied by means of labeled precursors of 14C-labeled amino acids and [14C]orotic acid in liver cells of hibernating, arousing, and active ground squirrels (Citellus undulatus). The investigations indicate that cycloheximide (CHI)-inhibited protein synthesis in liver cells of hibernating ground squirrels may occur on preexisting polyribosomes. A low level of protein synthesis in this state results not only from the Arrhenius dependence, but also from the dissociation of polyribosomes into monosomes. During arousal there is an intensive assembly of polyribosomes. This occurs even with the inhibition of RNA synthesis by actinomycin D, testifying to the presence of a pool of iRNA in liver cells, which is necessary to activate translation. The intensity of protein synthesis in arousal is also influenced by the activation of transcription.