Adrenocortical hormone effects in the central nervous system depend on steroid interaction with intracellular receptors, which belong to a superfamily of ligand-activated transcription factors. Using a combination of biochemical and molecular biology techniques, we have demonstrated: 1. the localization of mineralocorticoid receptors in the brain, with highest density present in hippocampus, lateral septum and some amygdaloid nuclei; 2. the arousal of a mineralocorticoid-specific behavior such as salt appetite, coincident with inhibition of the biosynthesis/activity of (Na+K)ATPase in some amygdaloid and hypothalamic nuclei; 3. the modulation of the biosynthesis/activity of the sodium pump by glucocorticoids, although for these hormones changes are stimulatory, as shown in the spinal cord and brain; 4. the reported steroid effects on the (Na+K)ATPase constitute an important mechanism of control of nervous system function, involving behavior, changes in excitability and neurotropism.