Exclusion of corticosterone from epithelial mineralocorticoid receptors is insufficient for selectivity of aldosterone action: in vivo binding studies

Endocrinology. 1996 Dec;137(12):5264-8. doi: 10.1210/endo.137.12.8940344.


Adrenalectomized weanling rats injected with [3H]aldosterone plus excess RU486, with or without a range of doses of nonradioactive aldosterone or corticosterone, show tissue-specific patterns of competition for tracer binding to mineralocorticoid receptors (MR). From detailed dose-response curves, corticosterone in vivo shows approximately 3% the apparent affinity of aldosterone for MR in colon and kidney, approximately 30% for those in the heart, and approximately 300% in the hippocampus. We interpret these data as evidence that 1) relatively low levels of aldosterone cross the blood-brain barrier; and 2) specificity-conferring mechanisms in addition to the exclusion of corticosterone from epithelial MR are required for selective aldosterone action in sodium homeostasis.

MeSH terms

  • Adrenalectomy
  • Aldosterone / metabolism*
  • Animals
  • Binding, Competitive
  • Colon / metabolism
  • Corticosterone / metabolism*
  • Epithelium / metabolism
  • Female
  • Hippocampus / metabolism
  • Hormone Antagonists / pharmacology
  • Kidney / metabolism
  • Mifepristone / pharmacology
  • Myocardium / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Mineralocorticoid / metabolism*
  • Weaning


  • Hormone Antagonists
  • Receptors, Mineralocorticoid
  • Mifepristone
  • Aldosterone
  • Corticosterone