RESUMO
OBJECTIVE: To investigate the effect of androgen on social behavior of male mice and underlying mechanisms. METHODS: After sham or gonadectomy (GDX) operation under deep anesthesia, adolescent (4-week-old) ICR male mice were divided into sham operation group (Sham), gonadectomy group (GDX), and gonadectomy with testosterone propionate (TP, 0.5, 1 mg•kg-1•d-1) supplementation group (GDX+TP)(TP supplementation was continued until the end of the experiment). By 13-week-old, social behaviors were tested. Testosterone levels in serum and the brain as well as arginine vasopressin (AVP) level in the brain were analyzed by ELISA. Androgen receptor (AR) level in the brain was analyzed by Western blot. Morphology of accessory olfactory bulb was detected by paraffin section. AVP expression in amygdala was detected by immunofluorescence. RESULTS: TP supplementation reversed GDX-induced inhibition of sexual behavior and invasive aggressive behavior. TP improved the social recognition ability rather than the general sense of smell of GDX mice. TP supplementation increased the level of testosterone in the brain and in serum and the expression of AR in the brain of GDX mice. TP increased the cell density of mitral cell layer, a projecting neuron in accessory olfactory bulb and elevated the level of AVP in the amygdala brain area. CONCLUSION: Androgen promotes social recognition by increasing the expression of AR in the brain, cell density in the mitral cell layer in accessory olfactory bulb, and AVP level in the amygdala, thus affecting social behavior of adult male mice.