Hormone-modulated rRNA gene activity is visualized by selective staining of the NOs

The role of Growth Hormone and Dexamethasone in the regulation of rRNA gene activity was evaluated on cultured human fibroblasts by the cyto-chemical method of selective silver staining. By this method the transcriptionally active r-gene clusters can be specifically visualized in individual cells. Statistically significant increases in the rate of rRNA transcriptional activity were demonstrated after hormone administration.