Impulse: The Premier Undergraduate Neuroscience Journal (Aug 2024)
Chronic administration of testosterone to adolescent male rats reduces social motivation
Abstract
The use of anabolic androgenic steroids (AAS), such as testosterone, is associated with a myriad of physiological and behavioral health concerns. Most notably, in both humans and rats, exposure to supraphysiological levels of testosterone has been shown to increase aggressive-like behaviors. However, it is unclear if testosterone enhances the motivation to engage in aggressive-type behaviors to begin with. To elucidate the effects of testosterone on the motivation to seek out a potentially aggressive encounter, rats were tested on a social motivation task in which physical contact between test and stimulus rats was prevented by a wire barrier, which eliminated the possibility of physical provocation. Relative to vehicle treated rats, rats treated with testosterone during adolescence exhibited lower levels of social motivation, as indicted by a reduction in the amount of time spent adjacent to the wire barrier. Over the course of the social motivation test, there were no differences between testosterone and vehicle treated rats in the frequency of rearing behavior and the total number of fecal boli, which suggests that the testosterone-induced reduction in social motivation occurred independent of changes in activity and emotionality, respectively. Consistent with previous studies, testosterone treatment during adolescence decreased total weight gain, increased the weights of the bulbourethral glands, and decreased the weights of the testes. These results suggest that the heightened levels of aggression following testosterone exposure that have been reported in other studies are likely not due to a greater motivation to seek out an interaction with a conspecific of the same sex. Abbreviations: ASS – Anabolic Androgenic Steroids; PND – Post Natal Day; HPA axis – Hypothalamic-Pituitary-Adrenal axis; HPG axis – Hypothalamic-Pituitary-Gonad axis
