Two Receptor Systems for Corticosterone in Rat Brain: Microdistribution and Differential Occupation

Abstract

Two receptor systems for corticosterone (CORT) can be distinguished in rat brain: mineralocorticoid-like or CORT receptors (CR) and glucocorticoid receptors (GR). The microdistribution and extent of occupation of each receptor population by CORT were studied. The CR system is restricted predominantly to the lateral septum and hippocampus. Within the hippocampus, the highest density occurs in the subiculum +/- CA1 cell field (144 fmol/mg protein) and the dentate gyrus (104 fmol/mg protein). Affinity of CR for CORT was very high (Kd, approximately 0.5 nM). The GR system has a more widespread distribution in the brain. The highest density for GR is in the lateral septum (195 fmol/mg protein), the dentate gyrus (133 fmol/mg protein), the nucleus tractus solitarii and central amygdala. Substant