Effects of Stress, Circadian Rhythms, and Dietary Sodium on Brain Cell-Nuclear Uptake of Aldosterone and Corticosterone (Steroid Receptors)
The binding of the adrenal steroid hormones aldosterone (ALD) and corticosterone (CORT) in brain cell-nuclei has been implicated as a necessary step in the behavioral and physiological actions of these hormones. In vivo uptake of radioactively labeled ALD and CORT in adrenalectomized (ADX) rats indicates a strong cell-nuclear localization of both of these hormones in limbic brain regions (such as hippocampus, septum and amygdala). However, assays of steroid uptake in ADX rats typically fail to account for the normal competition of assorted corticosteroids for corticoid binding sites in the brains of adrenal-intact subjects. In light of the greater binding affinity of the corticoid receptors for CORT than for ALD, and the greater plasma concentrations of CORT, it is possible that ALD is not bound by brain cell-nuclei in the normal, adrenal-intact subject. Moreover, description of the brain's in vivo regional uptake of these hormones in ADX rats, may be inaccurate due to labeling of heterogeneous binding sites by the single corticosteroid ligand under investigation.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign