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Psychopharmacology (Berl). 2004 Jan;171(3):298-305. Epub 2003 Oct 14.

Testosterone reinforcement: intravenous and intracerebroventricular self-administration in male rats and hamsters.

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Department of Cell and Neurobiology, Keck School of Medicine at the University of Southern California, Los Angeles 90033, USA.



Anabolic steroids are drugs of abuse. However, the potential for addiction remains unclear. Testosterone induces conditioned place preference in rats and oral self-administration in hamsters.


To determine if male rats and hamsters consume testosterone by intravenous (IV) or intracerebroventricular (ICV) self-administration.


With each nose-poke in the active hole during daily 4-h tests in an operant conditioning chamber, gonad-intact adult rats and hamsters received 50 microg testosterone in an aqueous solution of beta-cyclodextrin via jugular cannula. The inactive nose-poke hole served as a control. Additional hamsters received vehicle infusions.


Rats ( n=7) expressed a significant preference for the active nose-poke hole (10.0+/-2.8 responses/4 h) over the inactive hole (4.7+/-1.2 responses/4 h). Similarly, during 16 days of testosterone self-administration IV, hamsters ( n=9) averaged 11.7+/-2.9 responses/4 h and 6.3+/-1.1 responses/4 h in the active and inactive nose-poke holes, respectively. By contrast, vehicle controls ( n=8) failed to develop a preference for the active nose-poke hole (6.5+/-0.5 and 6.4+/-0.3 responses/4 h). Hamsters ( n=8) also self-administered 1 microg testosterone ICV (active hole:39.8+/-6.0 nose-pokes/4 h; inactive hole: 22.6+/-7.1 nose-pokes/4 h). When testosterone was replaced with vehicle, nose-poking in the active hole declined from 31.1+/-7.6 to 11.9+/-3.2 responses/4 h within 6 days. Likewise, reversing active and inactive holes increased nose-poking in the previously inactive hole from 9.1+/-1.9 to 25.6+/-5.4 responses/4 h. However, reducing the testosterone dose from 1 microg to 0.2 microg per 1 microl injection did not change nose-poking.


Compared with other drugs of abuse, testosterone reinforcement is modest. Nonetheless, these data support the hypothesis that testosterone is reinforcing.

[Indexed for MEDLINE]

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