Nervus terminalis lesions: I. No effect on pheromonally induced testosterone surges in the male hamster

The involvement of the nervus terminalis or terminal nerve in the pheromonally induced testosterone surge in the male hamster was investigated. Blood was collected from male hamsters not exposed to odor (baseline), and then a week later from the same hamsters exposed to the odor of vaginal discharge from an estrous female. Terminal nerve lesions, forebrain lesions, or sham surgeries were performed, and blood was collected again with and without odor stimulation. Serum testosterone levels were assessed by radioimmunoassay. None of the surgical procedures interrupted the ability of the male hamsters to demonstrate an increase in serum testosterone following exposure to the odor of an estrous female. We conclude that the terminal nerve is not necessary for this pheromonally mediated neuroendocrine reflex.