Steroid hormone induced gene expression requires translocation of hormone-receptor-dimers from the cytosol to the chromatin. The present study addresses the hypotheses of whether each NPC could be non-randomly recruited to translocate hormone-receptor-dimers to their target genes that are in turn located in limited domains of the chromatin. For this purpose glucocorticoid receptor (GR) expressing Xenopus laevis oocytes are microinjected with a potent glucocorticoid to target glucocorticoid initiated proteins (GIPs) and ribonucleoproteins (RNPs) to the nuclear envelope (NE) surface. Over a time scale of 90 seconds to 60 minutes after TA injection, nuclear envelope permeability and structure were investigated by fluorescence and atomic force microscopy. Passive nuclear envelope permeability for fluorescent macromolecules transiently decreased during import of GIPs (5.53% after 90 seconds of TA stimulation) and export of RNPs (10.35 % after 20 minutes of TA stimulation) visualized on the nuclear envelope surface at single molecule level. During transport of GIPs and RNPs, local areas of the nuclear envelope surface were found divided into at least two distinct populations of NPCs, transporting or resting ones that alternate with each other. We conclude that steroid hormone signalling to the nucleus occurs at selective sites of the nuclear envelope and involves predetermined NPCs. The route of transport of individual NPCs is most likely bi-directional.