Sex-specific effect of the anabolic steroid, 17α-methyltestosterone, on inhibitory avoidance learning in periadolescent rats

Abstract

The illicit use of anabolic androgenic steroids (AAS) has gained popularity among adolescents in the last decade. However, although it is known that exposure to AAS impairs cognition in adult animal models, the cognitive effects during adolescence remain undetermined. An inhibitory avoidance task (IAT) was used to assess the effect of AAS (17α-methyltestosterone; 17α-meT--7.5 mg/kg) in male and female periadolescent rats. A single injection of 17α-meT immediately before the footshock produced significant impairment of inhibitory avoidance learning in males but not females. Generalized anxiety, locomotion, and risk assessment behaviors (RAB) were not affected. Our results show that exposure to a single pharmacological dose of 17α-meT during periadolescence exerts sex-specific cognitive effects without affecting anxiety. Thus, disruption of the hormonal milieu during this early developmental period might have negative impact on learning and memory.

Keywords: Anabolic androgenic steroids; Anxiety; Cognition; Inhibitory avoidance learning; Periadolescent.

Figure 1. Effect of AAS on the IAT in adolescent rats

(A) Control male rats showed a significant increase in the crossover latency (sec) when compared Day 1 to Day 3. In contrast, during retention (Day 3) AAS-treated male rats showed a significant decreased in this latency. (B) Although a non-significant increase was observed in the crossover latency (sec) in control female rats when compared Day 1 to Day 3, they were not affected by AAS during retention (Day 3). **Two-Way ANOVA RM; p< 0.005. Males: Control n=9, AAS n=10; Females: Control n=30, AAS n=30. Error bars represent SEM.

Fig. 2. Effect of AAS on the EPM in adolescent rats

Exposure to AAS did not affect the time spent in the open arms (A, B), the open arms entries (C, D), or the total number of entries (E, F) on the EPM in either male (A, C, E) or female (B, D, F) rats. Control n=10, AAS n=10 for each male or female. Error bars represent SEM.