The pituitary gland undergoes important changes in cellular plasticity throughout life, consequently leading to hormonal output changes. The intermediate filament nestin plays a crucial role in cells that retain plasticity during development, aging and tumorigenesis. Here, we describe robust nestin immunoreactivity in glial-like cells of the intermediate lobe and in the vasculature of the developing, adult and aging pituitary gland. Additionally, we report a high incidence of spontaneous hyperplastic nodules in the anterior lobe of 24-month-old rats. In the nodules, nestin immunoreactivity is increased in blood vessels and in a few endocrine cells. We also found increased accumulation of nestin in hyperplastic glial-like cells of the intermediate lobe. This study suggests that nestin in the pituitary gland is implicated in age-related cellular plasticity.