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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/26 20:07:46」(JST)

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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 projections from the hypothalamus that terminate behind the anterior pituitary, and is also a store for the later release of neurohypophysial hormones.

Structure

The posterior pituitary consists mainly of neuronal projections (axons) of magnocellular neurosecretory cells extending from the supraoptic and paraventricular nuclei of the hypothalamus. These axons store and release neurohypophysial hormones oxytocin and vasopressin into the neurohypohyseal capillaries, from there they get into the systemic circulation (and partly back into the hypophyseal portal system). In addition to axons, the posterior pituitary also contains pituicytes, specialized glial cells resembling astrocytes assisting in the storage and release of the hormones.^[2]

Classification of the posterior pituitary varies, but most sources include the two regions below:

Pars nervosa: Also called the neural lobe or posterior lobe, this region constitutes the majority of the posterior pituitary and is the storage site of oxytocin and vasopressin. Sometimes (incorrectly) considered synonymous with the posterior pituitary, the pars nervosa includes Herring bodies and pituicytes.^[3]
Infundibular stalk: Also known as the infundibulum or pituitary stalk, the infundibular stalk bridges the hypothalamic and hypophyseal systems.

The median eminence is only occasionally included as part of the posterior pituitary. Other sources specifically exclude it from the pituitary.^[4]

A few sources include the pars intermedia as part of the posterior lobe, but this is a minority view. It is based upon the gross anatomical separation of the posterior and anterior pituitary along the cystic remnants of Rathke's pouch, causing the pars intermedia to remain attached to the neurohypophysis.

Function

Hormone secretion

Hormones known classically as posterior pituitary hormones are synthesized by the hypothalamus. They are then stored in neurosecretory vesicles regrouped into Herring bodies before being secreted by the posterior pituitary into the bloodstream.

Hormone	Other names	Symbol(s)	Main targets	Effect	Source
Oxytocin	Pitocin (trade name)	OT	Uterus, mammary glands	Uterine contractions; lactation	supraoptic and paraventricular nuclei
Vasopressin	Antidiuretic hormone, arginine vasopressin, argipressin	VP, AVP, ADH	Kidneys or Arterioles	Stimulates water retention; raises blood pressure by contracting arterioles, induces male aggression	supraoptic and paraventricular nuclei

Clinical significance

Insufficient secretion of vasopressin underlies diabetes insipidus, a condition in which the body loses the capacity to concentrate urine. Affected individuals excrete as much as 20 liters of dilute urine per day. Oversecretion of vasopressin causes the syndrome of inappropriate antidiuretic hormone (SIADH).

References

^ Embryology at unc.edu
^ Hatton, GI (September 1988). "Pituicytes, glia and control of terminal secretion." (PDF). The Journal of experimental biology 139: 67–79. PMID 3062122.
^ Histology image:14004loa from Vaughan, Deborah (2002). A Learning System in Histology: CD-ROM and Guide. Oxford University Press. ISBN 978-0195151732.
^ Median eminence at the US National Library of Medicine Medical Subject Headings (MeSH)

External links

www.pituitary.org — The Pituitary Network Association

Additional images

The posterior pituitary comprises the posterior lobe of the pituitary gland.
Hypothalamic nuclei

UpToDate Contents

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1. 中枢性尿崩症の臨床症状および原因 clinical manifestations and causes of central diabetes insipidus
2. 多尿および尿崩症の診断 diagnosis of polyuria and diabetes insipidus
3. 分娩の生理学 physiology of parturition
4. 夜間頻尿：臨床症状、診断、および治療治療 nocturia clinical presentation diagnosis and treatment

English Journal

Bifocal germinomas in the pineal region and hypothalamo-neurohypophyseal axis: Primary or metastasis?

Zhang H1, Qi ST2, Fan J1, Fang LX1, Qiu BH1, Liu Y1, Qiu XY1.
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia.J Clin Neurosci.2016 Dec;34:151-157. doi: 10.1016/j.jocn.2016.06.009. Epub 2016 Jul 28.
Whether bifocal germinomas (BFGs) synchronously presenting within the pineal region and the hypothalamo-neurohypophyseal axis (HNA) are primary germinomas of dual-origin remains to be elucidated. We analyzed MRI images and clinical features of 95 neurohypophyseal germinomas and 21 BFG patients and d
PMID 27475314

Ghrelin-Induced Enhancement of Vasopressin and Oxytocin Secretion in Rat Neurohypophyseal Cell Cultures.

Gálfi M1, Radács M1, Molnár Z1, Budai I1, Tóth G2, Pósa A3, Kupai K3, Szalai Z3, Szabó R3, Molnár HA4, Gardi J5, László FA6, Varga C3.
Journal of molecular neuroscience : MN.J Mol Neurosci.2016 Dec;60(4):525-530. Epub 2016 Oct 17.
The effects of ghrelin on vasopressin and oxytocin secretion were studied in 13-14-day cell cultures of isolated rat neurohypophyseal tissue. The vasopressin and oxytocin contents of the supernatant were determined by radioimmunoassay after a 1- or 2-h incubation. Significantly increased levels of v
PMID 27752928

Perifocal Inflammatory Reaction with Volume Fluctuation Caused by Diagnostic Radiation-Induced Regression in Germinoma Makes Histological Diagnosis Difficult despite Its Disappearance following Treatment: A Significant Pitfall and Countermeasures to It.

Yoneoka Y1, Yoshimura J, Okada M, Fujii Y.
Pediatric neurosurgery.Pediatr Neurosurg.2016 Nov 11. [Epub ahead of print]
We present a pediatric case of neurohypophyseal germinoma with a perifocal inflammatory reaction (PIR) with volume fluctuation caused by diagnostic radiation-induced regression (DRIR). On-target biopsy failed to confirm the histology because PIR hardly contained any germinoma cells. DRIR-related flu
PMID 27832656

Japanese Journal

Arg-vasopressin Facilitates Calcium Channel Currents in Osteoblasts

, , , , , , ,
The Bulletin of Tokyo Dental College 55(4), 241-244, 2014
… The hypothalamic nonapeptide and neurohypophyseal hormone arg-vasopressin (AVP), also known as antidiuretic hormone, is best known for its effects on water reabsorption in kidney. …
NAID 130004713445

Tandem duplications in the C-terminal domain of the mesotocin receptor exclusively identified among East Eurasian thrushes.

Abe Hideaki,Nishiumi Isao,Inoue-Murayama Miho
Journal of molecular evolution 77(5-6), 260-267, 2013-11-06
… Mesotocin is a neurohypophyseal hormone found in some non-mammalian vertebrates, including birds, reptiles, and amphibians. …
NAID 120005595850

遺伝子改変技術を用いたオキシトシンニューロンの蛍光タンパクによる可視化の試み

加藤明子,上田陽一,鈴木秀明
産業医科大学雑誌 35(2), 165-171, 2013-06-01
下垂体後葉ホルモンの一つであるオキシトシンは,視床下部室傍核および視索上核に局在する大細胞性神経分泌ニューロンの細胞体で産生され,下垂体後葉に投射した軸索終末から血中に分泌される.血中オキシトシンは,分娩時の子宮筋収縮や授乳時の射乳反射に関与することはよく知られている.最近,オキシトシン受容体が脳内にも豊富に存在し,親子の絆,信頼感などの高次脳機能に関与することが報告され,注目を集めている.これま …
NAID 110009615293

「neurohypophysial」

Posterior pituitary
	Pituitary gland. Posterior pituitary is in blue. Pars nervosa and infundibular stalk are not labeled, but pars nervosa is at bottom and infundibular stalk is at top.)
	Median sagittal through the hypophysis of an adult monkey. (Posterior lobe labeled at bottom right.)
Details
Latin	Pars nervosa glandulae pituitariae,; pars nervosa hypophyseos,; lobus posterior hypophyseos
Precursor	Neural tube (downward-growth of the diencephalon)
Artery	inferior hypophyseal artery
Vein	hypophyseal vein
Identifiers
Gray's	p.1275
MeSH	A06.407.747.734
NeuroLex ID	Neurohypophosis
Dorlands; /Elsevier	Posterior pituitary hormones
TA	A11.1.00.006
FMA	74628
	Anatomical terminology