Initial high dose steroid treatment of transplant recipients induces changes in the cytoplasmic glucocorticoid receptor (cGR) that may affect the mode of action of the drug. The cGR consists of functionally distinct isoforms of the GR and chaperone molecules, including FK binding protein 5 (FKBP5), that modulate GR signaling. Normal sensitivity to steroids requires expression of appropriate GR isoforms and the collaboration with FKBP5. Gene transactivation requires the GR-b isoform and is inhibited by excessive expression of the hGR-b isoform. Over expression of FKBP5 can attenuate steroid sensitivity by restraining translocation of the GR from cytoplasm to nucleus. We investigated the effect of bolus glucocorticoid (GC) treatment on the structure of the cGR complex by measuring the levels of GR isoform expression and FKBP5 transcription.