Glucocorticoid response in target cells closely correlates with glucocorticoid receptor (GR) level. We have compared the localization of GR (by immunocytochemimstry) and GR mRNA levels (by in situ hybridization) in steroid-sensitive and steroid-resistant subclones derived from the human CEM lymphoid cell line. In addition, GR was localized in lymphoid cells from patients with various hematological malignancies. In the absence of preincubation with the steroid, GR was localized at the light and electron microscopic level predominantly in the cytoplasm and to a weaker extent in the nucleus. In the presence of steroid, the GR was shown to translocate to the nucleus in the steroid-sensitive but not in the steroid-resistant cell lines. Furthermore, GR and GR mRNA levels were increased following glucocorticoid treatment of the sensitive cell line but not the resistant one. These data support a role for receptor regulation and translocation in the overall mechanism of glucocorticoid hormone action.
Presented at the Symposium on “Glucocorticoid Receptors: Evolution, Structure, Function and Abnormalities,” July 14 and 15, 1988, Osaka, Japan.
This work was supported by grants from the National Cancer Institute of Canada.