Presence of type I and type II/IB receptors for adrenocorticosteroid hormones in the inner ear

Hear Res. 1989 Sep;41(2-3):217-21. doi: 10.1016/0378-5955(89)90013-0.

Abstract

Aldosterone-Type I and dexamethasone-Type II/IB receptor complexes were identified in cytosol prepared from both cochlear and vestibular tissue samples. The specific binding capacity of Type I receptors in the cochlear tissues was approximately equal to that in the vestibular tissues. Likewise, the binding capacity of Type II/IB receptors in the cochlea was approximately equal to that in the vestibular endorgans. Based on the total specific binding measured with dexamethasone, the Type II/IB receptors appeared to outnumber the Type I receptors in cochlear and vestibular tissues by a factor of approximately 2.6; however, when adjustments were made for the probable cross-binding of dexamethasone to Type I receptors, these ratios were decreased to approximately 1.6. The existence of protein receptors for adrenocorticosteroid hormones demonstrated in the present study clearly suggests a mechanism whereby such hormones may directly regulate fluid and ionic gradients in the inner ear.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aldosterone / metabolism
  • Animals
  • Cochlea / metabolism
  • Cytosol / metabolism
  • Dexamethasone / metabolism
  • Ear, Inner / metabolism*
  • Homeostasis
  • Male
  • Rats
  • Receptors, Glucocorticoid / classification
  • Receptors, Glucocorticoid / metabolism*
  • Receptors, Mineralocorticoid
  • Vestibule, Labyrinth / metabolism

Substances

  • Receptors, Glucocorticoid
  • Receptors, Mineralocorticoid
  • dexamethasone receptor
  • Aldosterone
  • Dexamethasone