PMID- 16388806
OWN - NLM
STAT- MEDLINE
DCOM- 20060620
LR  - 20191210
IS  - 0018-506X (Print)
IS  - 0018-506X (Linking)
VI  - 49
IP  - 4
DP  - 2006 Apr
TI  - Self-administration of estrogen and dihydrotestosterone in male hamsters.
PG  - 519-26
AB  - Anabolic-androgenic steroids (AAS) are drugs of abuse. Previous studies have 
      shown that male and female hamsters self-administer testosterone (T) and other 
      AAS, suggesting that androgens are reinforcing in a context where athletic 
      performance is irrelevant. AAS are synthetic derivatives of T, which may be 
      aromatizable to estrogen and/or reducible to dihydrotestosterone (DHT). However, 
      we do not know which metabolites of T are reinforcing. To determine if DHT, 
      estradiol (E(2)), or DHT + E(2) are reinforcing, we tested 
      intracerebroventricular (icv) self-administration in male hamsters. The 
      hypothesis was that androgen reinforcement is sensitive to both androgenic and 
      estrogenic T metabolites. If so, hamsters would self-administer DHT, E(2), and 
      DHT + E(2). Twenty four castrated male hamsters (n = 8/group) received icv 
      cannulas and sc T implants for physiologic androgen replacement. One week later, 
      hamsters self-administered DHT (0.1, 1.0, 2.0 microg/microl), E(2) (0.001, 0.01, 
      0.02 microg/microl), or DHT + E(2), each for 8 days in increasing concentration 
      (4 h/day). Operant chambers were equipped with an active and inactive nose-poke. 
      At the medium concentration, hamsters self-administered DHT (active nose-poke: 
      47.9 +/- 13.9 responses/4 h vs. inactive: 18.7 +/- 4.8), E(2) (active: 44.8 +/- 
      14.9 vs. inactive: 16.6 +/- 2.6), and DHT + E(2) (active: 19.1 +/- 2.4 vs. 
      inactive: 10.4 +/- 2.4, P < 0.05). At the highest concentration, males 
      self-administered DHT (active: 28.3 +/- 7.7 vs. inactive: 15.0 +/- 3.5, P < 0.05) 
      and DHT + E(2) (active: 22.6 +/- 3.8 vs. inactive: 11.6 +/- 2.5, P < 0.05), but 
      not E(2). Hamsters did not self-administer the lowest concentrations of DHT, 
      E(2), or DHT + E(2). These results support our hypothesis that both androgenic 
      and estrogenic T metabolites are reinforcing. Together, they do not exert 
      synergistic effects.
FAU - DiMeo, Anita N
AU  - DiMeo AN
AD  - Neuroscience Program, Department of Cell and Neurobiology, Keck School of 
      Medicine at the University of Southern California, 1333 San Pablo St., BMT 401, 
      90033, USA.
FAU - Wood, Ruth I
AU  - Wood RI
LA  - eng
GR  - R01-DA12843/DA/NIDA NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20060104
PL  - United States
TA  - Horm Behav
JT  - Hormones and behavior
JID - 0217764
RN  - 0 (Anabolic Agents)
RN  - 08J2K08A3Y (Dihydrotestosterone)
RN  - 4TI98Z838E (Estradiol)
SB  - IM
MH  - Anabolic Agents/*administration & dosage
MH  - Analysis of Variance
MH  - Animals
MH  - Cricetinae
MH  - Dihydrotestosterone/*administration & dosage
MH  - Dose-Response Relationship, Drug
MH  - Drug Synergism
MH  - Dystonia/chemically induced
MH  - Estradiol/*administration & dosage/physiology
MH  - Injections, Intraventricular
MH  - Male
MH  - Mesocricetus
MH  - *Reinforcement, Psychology
MH  - Self Administration
EDAT- 2006/01/04 09:00
MHDA- 2006/06/21 09:00
CRDT- 2006/01/04 09:00
PHST- 2005/09/13 00:00 [received]
PHST- 2005/11/03 00:00 [revised]
PHST- 2005/11/16 00:00 [accepted]
PHST- 2006/01/04 09:00 [pubmed]
PHST- 2006/06/21 09:00 [medline]
PHST- 2006/01/04 09:00 [entrez]
AID - S0018-506X(05)00257-6 [pii]
AID - 10.1016/j.yhbeh.2005.11.003 [doi]
PST - ppublish
SO  - Horm Behav. 2006 Apr;49(4):519-26. doi: 10.1016/j.yhbeh.2005.11.003. Epub 2006 
      Jan 4.