Dihydrotestosterone and estrogen regulation of rat brain androgen-receptor immunoreactivity

Physiol Behav. 2000 Jun 1-15;69(4-5):445-53. doi: 10.1016/s0031-9384(99)00257-7.


Androgen-receptor upregulation that occurs with androgenic-anabolic steroid (AAS) administration may be mediated by AAS metabolites, dihydrotestosterone (DHT), and estrogen. Castrated and intact male rats received 14 s.c. daily injections of AAS (2 mg/kg testosterone cypionate, 2 mg/kg nandrolone decanoate, and 1 mg/kg boldenone undecylenate in sesame oil vehicle), DHT (5 mg/kg dihydrotestosterone), EB (5 mg/kg estradiol benzoate), or sesame oil vehicle. Approximately 18-24 h after the fourteenth injection, brain tissues were removed and processed immunocytochemically using the PG-21 androgen-receptor antibody. As reported before, castration eliminated AR-ir (androgen-receptor immunoreactivity) and AAS upregulated AR-ir in the ventromedial hypothalamus (VMHVL), medial amygdala (MePV), and medial preoptic area (MPOM). When compared to AAS, DHT fully upregulated AR-ir in the VM VL and MPOM and partially upregulated AR-ir in the MePV. EB treatment partially upregulated AR-ir in the VMHVL and MePV, but not in the MPOM of castrated rats. Because AR-ir in the MPOM was consistently upregulated by DHT or AAS, and not EB, androgen-receptor availability in this region may be mediated specifically via androgen receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amygdala / drug effects
  • Amygdala / metabolism
  • Anabolic Agents / pharmacology
  • Animals
  • Brain / drug effects
  • Brain / metabolism*
  • Cell Count / drug effects
  • Dihydrotestosterone / metabolism*
  • Estrogens / metabolism*
  • Image Processing, Computer-Assisted
  • Immunohistochemistry
  • Male
  • Nandrolone / analogs & derivatives*
  • Nandrolone / pharmacology
  • Nandrolone Decanoate
  • Preoptic Area / drug effects
  • Preoptic Area / metabolism
  • Rats
  • Rats, Long-Evans
  • Receptors, Androgen / metabolism*
  • Testosterone / analogs & derivatives*
  • Testosterone / pharmacology
  • Up-Regulation / drug effects
  • Ventromedial Hypothalamic Nucleus / drug effects
  • Ventromedial Hypothalamic Nucleus / metabolism


  • Anabolic Agents
  • Estrogens
  • Receptors, Androgen
  • Dihydrotestosterone
  • Testosterone
  • Nandrolone
  • Nandrolone Decanoate
  • testosterone 17 beta-cypionate
  • boldenone undecylenate