Nandrolone decanoate, behaviour and brain : animal experimental studies

Abstract

Abstract: Abuse of anabolic androgenic steroids (AAS) has been linked to psychiatric and physiological complications in humans. Studies have further found a relationship between AAS abuse and abuse of alcohol and other drugs. The main objective of this animal experimental thesis was to examine to what extent the AAS compound nandrolone decanoate (ND; Deca-Durabol® [15 mg/kg/day for 2 weeks]) induces behavioural and physiological changes in sexually mature male rats, when compared to oil-treated control rats. One aim was to investigate if ND stimulates establishment of dominance in a provocative and competitive test situation and if ND enhances reactivity towards physical provocations. Fleeing and freezing behaviours in response to a threatening stimulus were further studied. Another aim was to investigate whether ND stimulates voluntary ethanol consumption and if ND alters behavioural tolerance to ethanol. The results showed that ND stimulated dominance in a competitive and provocative situation, enhanced reactivity to physical provocations and decreased fleeing and freezing responses. ND treatment further increased ethanol consumption and induced behavioural tolerance to ethanol. This thesis also studied if NDinduced reactivity towards physical provocations and ethanol intake were altered when combining ND treatment with physical activity. It was found that physical exercise accentuated the enhancing effects of ND on reactivity and to some degree on ethanol intake. In this thesis, monoaminergic and opioidergic systems were also analysed. It was found that ND altered concentrations of serotonin, dynorphin B and enkephalin in various brain areas. Moreover, during the treatment period, ND-treated animals did not gain as much in body weight as controls. ND treatment also induced thymus atrophy and increased the weight of the adrenal glands. Taken together, the results from this thesis suggest that abuse of ND may constitute a risk factor for induction of behavioural complications, such as increased aggression and enhanced alcohol drinking. ND abuse may further affect physiological parameters like the hypothalamus-pituitary-adrenal axis and neurotransmitter concentrations. These results hopefully bear relevance for further research and in clinical settings when in contact with individuals abusing AAS.