Reinforcing aspects of androgens

Area of Science:

• Neuroscience
• Pharmacology
• Endocrinology

Background:

• Androgenic-anabolic steroids (AAS) are frequently abused for performance enhancement, leading to health issues and controlled substance classification.
• A two-stage model of AAS dependence suggests initial use for anabolic effects followed by dependence on psychoactive properties.
• Human studies face challenges in distinguishing direct psychoactive effects from psychological dependence on anabolic effects.

Purpose of the Study:

• To investigate the reinforcing properties of androgens using animal models.
• To explore the neural mechanisms underlying androgen reinforcement.
• To compare the reinforcing potential of androgens to other known drugs of abuse.

Main Methods:

• Conditioned place preference tests in rats and mice.
• Self-administration studies (oral, intravenous, intracerebroventricular) in hamsters.
• Intracerebroventricular testosterone administration in hamsters and nucleus accumbens injections in rats.
• Assessment of effects using dopamine receptor antagonists.

Main Results:

• Testosterone induced conditioned place preference in rats and mice.
• Hamsters voluntarily self-administered testosterone via multiple routes, with some self-administering to lethal levels.
• Testosterone injections into the nucleus accumbens of male rats created a conditioned place preference, blocked by dopamine antagonists.
• Androgen reinforcement appears mediated by the mesolimbic dopamine system.

Conclusions:

• Androgen reinforcement is mediated by the brain, specifically the mesolimbic dopamine system.
• Testosterone acts as a mild reinforcer, similar to caffeine or nicotine, rather than a potent drug of abuse like cocaine.
• The potential for androgen addiction warrants further investigation.