Dexamethasone treatment affects nuclear glucocorticoid receptor and glucocorticoid response element binding activity in liver of rats (Rattus norvegicus) during aging.
Aging is associated with marked changes in the biochemical processes of many organs. Basal and glucocorticoid induced of liver nuclear glucocorticoid receptor (GR) on the level of protein expression and DNA-binding activity were investigated at different ages (3, 6, 12, 18 and 24 months old) in two groups of rats in: untreated and dexamethasone treated. The results showed a significant decline of GR protein immunopurified from untreated rats of advanced age. In dexamethasone-treated rats, the quantity of GR protein was lower than in controls at all ages. The interactions of liver nuclear proteins with radioactively labelled synthetic oligonucleotide analogue containing consensus GRE sequence were analysed during aging. The results showed that GRE binding activity demonstrated a decrease both in untreated and in dexamethasone treated rats. However, relative to untreated rats, dexamethasone treatment resulted in a significant increase in GRE binding at all ages, except that of three months old animals. In conclusion, the observed alterations in GR protein expression and its DNA binding activity may play a role in the changes of the cell response to glucocorticoid during aging.
Vujcić
Miroslava T
MT
Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, Njegoseva 12, P. O. Box 473, 11001 Belgrade, Serbia. mvujcic@chem.bg.ac.yu <mvujcic@chem.bg.ac.yu>
Velicković
Natasa
N
Ruzdijić
Sabera
S
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D005938:Glucocorticoids / Q000378:metabolism; D047468:Immunoprecipitation; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D020218:Response Elements / Q000235:genetics*
D005938:Glucocorticoids; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone