Up-regulation of androgen receptor immunoreactivity in the rat brain by androgenic-anabolic steroids.

To characterize central nervous system changes that occur with anabolic steroid abuse in humans, immunocytochemical localization of androgen receptors in the brains of 10 intact and 10 castrated male rats was conducted after the administration of high levels of androgenic-anabolic steroids (AAS; 14 daily injections of sesame oil or a cocktail of 2 mg/kg testosterone cypionate, 2 mg/kg nandrolone decanoate, and 1 mg/kg boldenone undecylenate). In normal intact oil-treated males, nuclear androgen receptor immunoreactivity was present in many 'classical' and 'non-classical' androgen target sites in the brain. Administration of AAS increased the intensity of immunoreactivity in most classical androgen target sites and increased both the intensity of immunoreactivity and number of immunoreactive cells in most non-classical androgen target sites. These results may suggest that androgen receptors in the brain are up-regulated by AAS. The simultaneous androgen receptor up-regulation in these regions by AAS may account for the complex anabolic steroid abuse syndrome. Consistently, androgen receptor immunoreactivity in most brain regions was reduced or absent after castration, suggesting that endogenous androgen levels are necessary for normal androgen receptor immunoreactivity. These results identify the distribution of one central nervous system mechanism modified by AAS.