Nandrolone decanoate enhances hypothalamic biogenic amines in rats.

TAMAKI, T., T. SHIRAISHI, H. TAKEDA, T. MATSUMIYA, R. R. ROY, and V. R. EDGERTON. Nandrolone Decanoate Enhances Hypothalamic Biogenic Amines in Rats. Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 32-38, 2003. Purpose: To identify possible mechanisms for an anabolic-androgenic steroid induced increase in aggressive behavior and work capacity, the levels of some biogenic amines considered to be closely related to a systemic hyper-adrenergic state were measured in selected regions of the brain. Methods: Wistar male rats were divided randomly into five groups: nontreated (control), oil-vehicle-treated (vehicle) or one of three (therapeutic dose and 10- or 100-fold higher dose) anabolic-androgenic steroid-treated (steroid-1, -2, -3) groups. Rats in the steroid and vehicle groups were given a single dose of nandrolone decanoate or oil vehicle, respectively, one week before tissue sampling. The levels of norepinephrine (NE) and its metabolite, 4-hydroxy-3-methoxyphenylglycol (MHPG), serotonin (5-HT) and its metabolite, 5-hydroxy- indole-3-acetic acid (5-HIAA) were measured in the cerebral cortex, hypothalamus and cerebellum by high-performance liquid chromatography. Immunostaining for c-fos was performed as a confirmation of increased neural activity. Results: The levels of NE and MHPG were increased by ~2- and ~7-fold in the hypothalamus of the steroid-2 compared with the control and vehicle groups. The levels of 5-HT and 5-HIAA were ~40 and ~50% higher in the steroid-2 compared with the control and vehicle groups. A significantly higher number of c-fos expressing neurons were observed in the periventricular region of the steroid-2 than the control and vehicle groups, indicating enhanced neuronal activity after nandrolone decanoate treatment. Conclusions: The present results, combined with previously reported findings of physical performance enhancement after anabolic-androgenic steroid treatment, are consistent with the interpretation that elevated levels of adrenergic and serotonergic amines in the hypothalamus could contribute to aggressive behaviors as well as improved physical performance. Key Words: NANDROLONE-DECANOATE, HYPOTHALAMUS, NOREPINEPHRINE, SEROTONIN, C-FOS