Age-dependent changes in rat liver steroid hormone receptor proteins.

The formation of the steroid hormone-receptor protein complex in rat liver cytosol was investigated as a function of rat age. As reported earlier there was no age-related change in the concentration of receptor proteins in rat liver cytosol. The affinity of the specific receptor protein for both dexamethasone and corticosterone, however, decreased with age. An age-related decrease was observed in the concentration of steroid hormones that were associated with the specific receptor protein responsible for translocation of the nucleus. A reciprocal age-dependent increase in non-specific protein binding of the hormone occurred.