The Anabolic Androgenic Steroid Testosterone Propionate Decreases Recognition Memory in Adult Male Rats

Abstract

Although there are therapeutic applications of the Anabolic Androgenic Steroids (AAS), the predominant use implies the illicit self-administration by athletes and adolescents. In this respect, AAS abuse is associated with untoward effects on brain and behavior. Exposure to supraphysiological doses of AAS leads to changes in anxiety and aggression, but their effects on cognitive functions are poorly understood. We investigated the effects of the AAS testosterone propionate (TP), acutely or chronically administered in supraphysiological doses, on memory in rats. Experiment I - Adult male Wistar rats were treated once with vehicle (Control group, n = 5) or TP (10 mg/kg, n = 5). Behavioral experiments were performed 60 minutes after the single injection, and included the evaluation of spatial working memory and recognition memory. Experiment II - The rats received repeated daily administration of vehicle (n = 6) or TP (n = 7) for 40 days. Behavioral experiments started 23 hours after the last injection. After behavioral procedures, the animals were euthanized, the blood was collected for biochemical analyses and testicles were removed and weighted. Regarding the behavioral assessment, rats chronically treated with TP presented decreased time exploring the novel object when compared to control group. Rats that were treated acutely showed no significant difference compared with control. Acute or chronic treatments with TP were not effective in promoting changes in spatial working memory. Additionally, chronic treatment with TP induced significantly increases in biochemistry marker the enzyme glutamate pyruvate transaminase (SGPT) and a reduction in testicular weight as compared with control. Even though not interfering with spatial working memory performance, AAS abuse could induce deficit on recognition memory.