Pituicyte
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Pituicytes are
glial cell Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myel ...
s of the
posterior pituitary The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. The posterior pituitary is not glandular as is the anterior pituitary. Instead, it is largely a collection of axonal ...
. Their main role is to assist in the storage and release of
neurohypophysial hormone The neurohypophysial hormones form a family of structurally and functionally related peptide hormones. Their representatives in humans are oxytocin and vasopressin. They are named after the location of their release into the blood, the neurohyp ...
s.


Structure

Pituicytes are located in the pars nervosa of the posterior pituitary and interspersed with unmyelinated
axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...
s and
Herring bodies Herring bodies or neurosecretory bodies are structures found in the posterior pituitary. They represent the terminal end of the axons from the hypothalamus, and hormones are temporarily stored in these locations. They are neurosecretory terminals. ...
. They generally stain dark purple with an
H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diag ...
and are among the easiest structures to identify in the region. Pituicytes have an irregular and branched shape which resembles that of another type of glial cell: the
astrocyte Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of e ...
. Like astrocytes, their cytoplasm presents specific
intermediate filament Intermediate filaments (IFs) are cytoskeletal structural components found in the cells of vertebrates, and many invertebrates. Homologues of the IF protein have been noted in an invertebrate, the cephalochordate '' Branchiostoma''. Intermed ...
s made up of glial fibrillary acidic protein (GFAP).


Function

Pituicytes are similar to astrocytes, another type of glial cell. Their main role is to assist in the storage and release of hormones of the posterior pituitary. Pituicytes surround axonal endings and regulate hormone secretion by releasing their processes from these endings.


Clinical significance

Pituicytomas are rare tumors that arise from pituicytes. They may be mistaken for the much more common
pituitary adenoma Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas.craniopharyngioma A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence ...
and
meningioma Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing ...
. Symptoms from the
mass effect ''Mass Effect'' is a military science fiction media franchise created by Casey Hudson, Drew Karpyshyn and Preston Watamaniuk. The franchise depicts a distant future where humanity and several alien civilizations have colonized the known unive ...
of the tumor usually include vision disorders, and less often headaches,
hypopituitarism Hypopituitarism is the decreased (''hypo'') secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is know ...
(decreased function of the pituitary gland), fatigue, and decreased libido.


References


External links


NIF Search - Pituicyte
via the
Neuroscience Information Framework The Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/genomic resources and provides many auth ...
{{Authority control Histology de:Pituicyt