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NORMAN S. ANDERSON, DARRELL D. FANESTIL, Corticoid Receptors in Rat Brain: Evidence for an Aldosterone Receptor, Endocrinology, Volume 98, Issue 3, 1 March 1976, Pages 676–684, https://doi.org/10.1210/endo-98-3-676
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The existence of high and low affinity mineralocorticoid-binding macromolecules (receptors) has been demonstrated in vitro in cytosols derived from the adrenalectomized rat brain by the specific binding of [3H]aldosterone (3H-A). The highaffinity aldosterone sites can be distinguished from those sites which have a higher affinity for either [3H]dexamethasone (3H-DM) or [3H]corticosterone (3H-B) on the basis of selectivity for spirolactone SC-9420 or non-radioactive A, DM, and B. The binding of 3H-A to the receptors was maximal after 2 hours of incubation at 0-4 C. No significant binding of3H-A to the receptors could be demonstrated when incubations of the radioactive ligandwere performed at either 20 or 37 C, indicating that the receptor is heat-labile. Scatchard analysis of the 3H-A binding data over a 200-fold concentration range of 3H-A indicated that there are two binding sites for aldosterone, a highaffinity component (a,) with a Kd ≅ 1.5 × 10-9M and a low-affinity component (a2) with a Kd ≅ 6.3 × 10-8M. A similar study using 3H-DM as the radioactive ligand demonstrated only one site for the 3H-DM binding with a Kd = 6.2 ×10-9M. The presence of specific aldosterone receptors in the brain with high affinity, limited capacity, and selectivity for aldosterone suggests a possible extra-renal mechanism of action of the hormonein or mediated through the CNS. (Endocrinology98: 676, 1976)
