[Effect of cytoplasmic factors on cell nucleus binding of glucocorticoid receptor complexes in the rat liver of two age groups].

The nuclei binding of activated glucocorticoid receptor complexes (GRC) was significantly diminished in old, unstressed rats compared with young ones. In animals killed at different times after physiological stress there were no significant age-dependent differences in nuclei binding of GRC, which recurred in the cytoplasm after 60, 120 and 180 min, resp. Addition of Ca2+ and ATP, resp., to the incubation system increased the nuclei bound part of GRC, especially in young animals. ATP-stimulated translocation promoter (ASTP), isolated from rat liver cytosol, raised the nuclei binding of GRC in both age groups, whereby the increase was only significant in young animals. In cytosol of old rats ASTP were found in a lower concentration; moreover, the reaction between ASTP, GRC, and the template seems to be impaired.