In human cells, ribosomal genes are interspersed by 30 kb long intergenic spacers (IGS). Recently it has been found that all, or almost all, parts of IGS may be transcribed, and at least some of them play important role in the regulation of rDNA transcription, maintenance of nucleolar architecture and reaction of the cell nucleus to the stress. But, since each cell contains hundreds not quite identical copies of IGS, the structure and functions of this locus remain poorly understood, dynamics of its products has not been studied specially. In this study we used qPCR to measure expression levels of various ribosomal and spacer regions at different times after inhibition of the transcription by ActD. This approach allowed us to measure real or extrapolated half-life times of some IGS loci. Our study reveals characteristic dynamic patterns suggestive of various pathways of RNA utilization and decay.