Characterization of alpha-adrenoceptor subtypes in the corpus cavernosum of patients undergoing sex change surgery

J Urol. 1999 Nov;162(5):1793-9.


Purpose: To characterize the subtypes of alpha1- and alpha2-adrenoceptors in the human corpus cavernosum from patients undergoing sex change surgery.

Materials and methods: Saturation and competition radioligand binding studies were performed for characterization at the protein level. Alpha1-adrenoceptors were labeled with [3H]prazosin and [3H]tamsulosin, while alpha2-adrenoceptors were labeled with [3H]RX 821002. Alpha1-adrenoceptor subtype mRNA was additionally determined by reverse-transcriptase polymerase chain reaction and RNase protection assays.

Results: Human corpus cavernosum expressed approximately 32 and approximately 22 fmol./mg. protein alpha1- and alpha2-adrenoceptors, respectively. Competition studies with the alpha1A-selective antagonists 5-methylurapidil and (+)-niguldipine and the alpha1D-selective BMY 7378 revealed a mixed alpha1A/alpha1B-adrenoceptor population with no evidence for alpha1D-adrenoceptor protein. In contrast alpha1D-adrenoceptors were readily detected at the mRNA level. Competition binding studies with the alpha2A-selective oxymetazoline and the alpha2B-selective prazosin and ARC 239 revealed a homogeneous population of alpha2A-adrenoceptors.

Conclusions: We conclude that human corpus cavernosum expresses predominantly alpha1A-, alpha1B- and alpha2A-adrenoceptor protein; additionally the alpha1D-adrenoceptor is present at the mRNA level.

Publication types

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

MeSH terms

  • Adrenergic alpha-Antagonists / pharmacokinetics
  • Binding, Competitive
  • Disorders of Sex Development / surgery
  • Dose-Response Relationship, Drug
  • Humans
  • Idazoxan / analogs & derivatives
  • Idazoxan / pharmacokinetics
  • Male
  • Penis / chemistry*
  • Penis / metabolism
  • Penis / surgery
  • Prazosin / pharmacokinetics
  • Receptors, Adrenergic, alpha / analysis*
  • Receptors, Adrenergic, alpha / metabolism
  • Sulfonamides / pharmacokinetics
  • Tamsulosin


  • Adrenergic alpha-Antagonists
  • Receptors, Adrenergic, alpha
  • Sulfonamides
  • 2-methoxyidazoxan
  • Tamsulosin
  • Prazosin
  • Idazoxan