A pituicyte is a type of glial cell found in the posterior pituitary.
Pituicytes are specialized cells crucial to the function of the posterior pituitary gland, also known as the neurohypophysis. Unlike the glandular cells found in the anterior pituitary, the posterior pituitary is primarily composed of the axons of neurosecretory neurons originating from the hypothalamus, specifically from the supraoptic and paraventricular nuclei.
Key Characteristics of Pituicytes
- Type of Cell: Pituicytes are glial cells. Glial cells are non-neuronal cells that provide support, nourishment, and insulation to neurons. In the central nervous system, common glial cells include astrocytes, oligodendrocytes, microglia, and ependymal cells. Pituicytes are the principal glial cells of the posterior pituitary.
- Location: They reside specifically within the posterior pituitary gland.
Role in Hormone Management
As highlighted in the provided reference, the main role of pituicytes is to assist in the storage and release of neurohypophysial hormones.
These neurohypophysial hormones are synthesized by neurons in the hypothalamus and transported down their axons into the posterior pituitary gland, where they are stored in nerve terminals. The primary hormones stored and released here are:
- Antidiuretic Hormone (ADH), also known as Vasopressin, which regulates water reabsorption in the kidneys.
- Oxytocin, which plays roles in social bonding, labor contractions, and milk ejection.
Pituicytes surround these nerve terminals and are thought to regulate the access of hormones to the bloodstream. By changing their shape and processes, they can either cover the nerve terminals, hindering hormone release, or retract, allowing the hormones to be released into the surrounding capillaries. This interaction makes pituicytes important modulators of hormone secretion from the posterior pituitary.
Summary Table
| Feature | Description |
|---|---|
| Cell Type | Glial cell |
| Location | Posterior pituitary (Neurohypophysis) |
| Main Function | Assist in the storage and release of neurohypophysial hormones (like ADH and Oxytocin) |
In essence, while the hormones are produced in the hypothalamus and released from the posterior pituitary, pituicytes act as the essential support staff within the posterior pituitary, helping to control the precise timing and amount of hormone release into the bloodstream.
