 Tanycytes in adult mammals are found in the ventricular system and the circumventricular organs.They are most numerous in the third ventricle of the brain, but can also be seen in the spinal cord radiating from the ependyma of the central canal to the spinal cord surface.Tanycytes represent approximately 0.6% of the population of the lateral ventricular wall, as described by Doetsch et al.