Age-dependent activation of glucocorticoid receptors in the cerebral hemispheres of male rats.
The binding of [3H]dexamethasone-receptor complexes to purified nuclei was studied in the cerebral hemispheres of immature (3-week-old) and mature (26-week-old) Long-Evans male rats to determine the age-related changes, if any, in the physicochemical properties of glucocorticoid receptors. Our data show that heat activation (for 45 min at 25 degrees C) significantly enhances the nuclear binding of [3H]dexamethasone-receptor complexes in rats of both ages, with a greater magnitude in immature rats. Ca2+ activation (20 mM Ca2+ for 45 min at 0 degree C) also enhances the nuclear binding of bound receptor complexes but to a similar extent at both ages. These findings indicate that some of the physicochemical properties (e.g. heat activation) of glucocorticoid receptor change, while others (e.g. Ca2+ activation) remain unchanged at different phases of the lifespan.
Department of Physiology-Anatomy, University of California, Berkeley 94720.
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Sharma
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Timiras
D000375:Aging; D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000378:metabolism; D007700:Kinetics; D008297:Male; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000378:metabolism*
D011965:Receptors, Glucocorticoid; D003907:Dexamethasone