2. Testosterone treatment

Mice were castrated and rested for 48 h followed by intraperitoneal injection (100 μL/mouse) subcutaneously with sesame oil alone and with testosterone (300 ng/100 μL; Sigma, St. Louis, MO) dissolved in sesame oil. Mice were euthanized by CO₂ anesthesia followed by cervical dislocation, and then the cerebrum, hypothalamus, pituitary gland, and stomach were collected 24 h after treatment. We obtained the fundus part of the stomach and the front part of cerebrum. For dissection of the hypothalamus and pituitary gland, we removed brain from skull and placed ventral side up. Using curved forceps, we took out the pituitary gland from hypophyseal fossa, and then pushed the curved part of forceps down around the hypothalamus and pinched it out.