6533b7d0fe1ef96bd125a1f6

RESEARCH PRODUCT

Effects of chronic administration with high doses of testosterone propionate on behavioral and physiological parameters in mice with differing basal aggressiveness

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The effects of testosterone propionate, an anabolic-androgenic steroid, on the behavior displayed during a social encounter by gonadally intact male mice were investigated. Animals were distributed into three groups according to their attack latency in a pre-screening test (high-, moderate-, and low-attacking mice) and each group received weekly injections of 60 or 120 mg/kg of testosterone or sesame oil for 10 weeks. Behavioral tests were then carried out. Afterwards, organs were weighed and blood samples collected in order to obtain hormonal data. Treatment had a differential impact on attack in the three groups of animals. Only the high-attacking testosterone-treated mice showed lower total duration of attack than their controls. Those that received 60 mg/kg spent more time exhibiting exploratory behaviors. As an index of the anabolic activity of the drug, all testosterone-treated mice had heavier kidneys and, as an index of the androgenic activity of testosterone propionate, they had heavier seminal vesicles, lighter testes, and showed higher testosterone levels in a dose-dependent way than their controls. Hence, the effect of treatment on peripheral physiological parameters was similar in all three groups whereas behavioral effects differed depending on basal aggressiveness, considered a characteristic of coping style.