Comparison of glucocorticoid receptors in various tissues of adult and senescent rats.

The specific [3H]-dexamethasone binding ability of the cytosols of divergent tissues such as kidney, testis and heart were examined in adult (2- to 3-month-old) as well as in senescent (20- to 24-month-old) male adrenalectomized Sprague-Dawley rats. Scatchard analysis showed the presence of a single class of high affinity binding sites in all these tissues from both adult and aged animals. No significant age-related changes in receptor binding site concentration, affinity or steroid specifities were apparent in either kidney, testis or heart. In addition, no age-related changes were observed in in vivo or in vitro nuclear binding of the [3H]-dexamethasone-receptor complexes in all the tissues examined. It was concluded that aging does not alter glucocorticoid receptor concentration, affinity or its ability to bind to nuclei in these diverse tissues examined.