Reinforcing aspects of androgens.
Are androgens reinforcing? Androgenic-anabolic steroids (AAS) are drugs of abuse. They are taken in large quantities by athletes and others to increase performance, often with negative long-term health consequences. As a result, in 1991, testosterone was declared a controlled substance. Recently, Brower [K.J. Brower, Anabolic steroid abuse and dependence. Curr. Psychiatry Rep. 4 (2002) 377-387.] proposed a two-stage model of AAS dependence. Users initiate steroid use for their anabolic effects on muscle growth. With continued exposure, dependence on the psychoactive effects of AAS develops. However, it is difficult in humans to separate direct psychoactive effects of AAS from the user's psychological dependence on the anabolic effects of AAS. Thus, studies in laboratory animals are useful to explore androgen reinforcement. Testosterone induces a conditioned place preference in rats and mice, and is voluntarily consumed through oral, intravenous, and intracerebroventricular self-administration in hamsters. Active, gonad-intact male and female hamsters will deliver 1 microg/microl testosterone into the lateral ventricles. Indeed, some individuals self-administer testosterone intracerebroventricularly to the point of death. Male rats develop a conditioned place preference to testosterone injections into the nucleus accumbens, an effect blocked by dopamine receptor antagonists. These data suggest that androgen reinforcement is mediated by the brain. Moreover, testosterone appears to act through the mesolimbic dopamine system, a common substrate for drugs of abuse. Nonetheless, androgen reinforcement is not comparable to that of cocaine or heroin. Instead, testosterone resembles other mild reinforcers, such as caffeine, nicotine, or benzodiazepines. The potential for androgen addiction remains to be determined.
Wood
Ruth I
RI
Department of Cell and Neurobiology, Keck School of Medicine at the University of Southern California, 1333 San Pablo Street, BMT 401, Los Angeles, CA 90033, USA. riw@usc.edu
D000284:Administration, Oral; D045930:Anabolic Agents / Q000008:administration & dosage; D000728:Androgens / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004298:Dopamine / Q000502:physiology; D005260:Female; D006801:Humans; D007276:Injections, Intraventricular; D008297:Male; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology; D051381:Rats; D012054:Reinforcement, Psychology; D012646:Self Administration; D012727:Sex Characteristics; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000523:psychology
D045930:Anabolic Agents; D000728:Androgens; D004298:Dopamine