View source for Pituitary gland

{{Short description|Endocrine gland of the brain}}
{{Infobox brain
| Name        = Pituitary gland
| Latin       = glandula pituitaria, hypophysis, hypophysis cerebri
| Image       = Hypophyse.png
| Caption     = Lateral view
| Width       = 200
| Image2      = 1806 The Hypothalamus-Pituitary Complex.jpg
| Caption2    = Lateral view of [[hypothalamus]]–pituitary complex
| Precursor   = Neural and oral [[ectoderm]], including [[Rathke's pouch]]
| System      = [[Endocrine system]]
| Artery      = [[Superior hypophyseal artery]], infundibular artery, prechiasmal artery, [[inferior hypophyseal artery]], capsular artery, artery of the inferior cavernous sinus<ref>{{cite journal |vauthors=Gibo H, Hokama M, Kyoshima K, Kobayashi S | title = [Arteries to the pituitary] | journal = Nippon Rinsho | volume = 51 | issue = 10 | pages = 2550–4 | year = 1993 | pmid = 8254920}}</ref>
| Vein        =
}}

The '''pituitary gland''' or '''hypophysis''' is an [[endocrine gland]] in [[vertebrate]]s. In [[human]]s, the pituitary gland is located at the base of the [[human brain|brain]], protruding off the bottom of the [[hypothalamus]]. The pituitary gland and the [[hypothalamus]] control much of the body's [[endocrine system]].<ref name="Saladin">{{cite book |last1=Saladin |first1=Kenneth S. |title=Anatomy & physiology: the unity of form and function |date=2012 |publisher=McGraw-Hill |location=New York, NY |isbn=9780073378251 |pages=499–503 |edition=6th}}</ref> It is seated in part of the [[sella turcica]], a [[fossa (anatomy)|depression]] in the [[sphenoid bone]], known as the [[hypophyseal fossa]]. The human pituitary gland is [[ovoid|oval shaped]], about 1 cm in diameter, {{convert|0.5 - 1|g|oz}} in weight on average, and about the size of a [[kidney bean]].<ref name="Hall2011">{{cite book |last1=Hall |first1=John E. |last2=Guyton |first2=Arthur C. |title=Guyton and Hall textbook of medical physiology |date=2011 |publisher=Saunders/Elsevier |location=Philadelphia, PA |isbn=9781416045748 |page=895 |edition=12th}}</ref><ref name="Standring2016">{{cite book |last1=Standring |first1=Susan |title=Gray's anatomy: the anatomical basis of clinical practice |date=2016 |publisher=Elsevier |location=Philadelphia, PA |isbn=9780702052309 |page=499 |edition=41st}} Digital version.</ref>

There are two main lobes of the pituitary, an [[anterior pituitary|anterior lobe]], and a [[posterior pituitary|posterior lobe]] joined and separated by a small [[intermediate lobe]]. The anterior lobe (adenohypophysis) is the glandular part that produces and secretes several [[hormone]]s. The posterior lobe (neurohypophysis) secretes [[neurohypophysial hormone]]s produced in the [[hypothalamus]]. Both lobes have different origins and they are both controlled by the hypothalamus. 

[[Hormone]]s secreted from the pituitary gland help to control [[development of the human body|growth]], [[blood pressure]], energy management, all functions of the [[sex organ]]s, [[thyroid gland]], [[metabolism]], as well as some aspects of [[pregnancy]], [[childbirth]], [[breastfeeding]], [[osmoregulation|water/salt concentration]] at the [[kidney]]s, temperature regulation, and pain relief.

== Structure ==
In humans, the pituitary gland rests upon the [[hypophyseal fossa]] of the [[sphenoid bone]], in the center of the [[middle cranial fossa]]. It sits in a protective bony enclosure called the [[sella turcica]], covered by a fold of [[dura mater]] known as the  [[diaphragma sellae]].<ref>{{cite book |title=Gray's Clinical Anatomy |publisher=Elsevier Health Sciences |year=2011 |isbn=978-1-4377-3580-2 |editor-last=Mancall |editor-first=Elliott L. |page=154 |chapter=Cranial Fossae |editor-last2=Brock |editor-first2=David G. |chapter-url=https://books.google.com/books?id=R6ARC5tdhtYC&pg=PA154}}</ref> 

The pituitary gland is composed of the [[anterior pituitary]], the [[posterior pituitary]], and an [[pars intermedia|intermediate lobe]] that joins them.<ref>{{cite journal |vauthors=Ganapathy MK, Tadi P | title = Anatomy, Head and Neck, Pituitary Gland |journal=StatPearls [Internet] | publisher = StatPearls Publishing | date = Jan 2020 | pmid = 31855373 | url = https://www.ncbi.nlm.nih.gov/books/NBK551529/ | access-date = 24 Sep 2020}}</ref> The intermediate lobe is [[avascular]] and almost absent in humans, but  in many other animals, it is distinct. The intermediate lobe in rats and mice have been extensively studied for the development of the pituitary and its functions.<ref name=":0">{{Cite book|title = The Pituitary -|url = https://archive.org/details/pituitaryrdediti00melm|url-access = limited|last = Melmed|first = Shlomo|publisher = Academic Press is an imprint of Elsevier|year = 2011|isbn = 978-0-12-380926-1|location = San Diego, CA |pages = [https://archive.org/details/pituitaryrdediti00melm/page/n25 23]–25|edition = Third}}{{deadlink|date=April 2025}}</ref> In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary, which is an extension of the [[hypothalamus]].<ref name=":0" />

The height of the pituitary gland ranges from 5.3 to 7.0 mm. The volume of the pituitary gland ranges from 200 to 440&nbsp;mm<sup>3</sup>.<ref name=":1">{{Cite journal |last1=Yadav |first1=Pratiksha |last2=Singhal |first2=Shubham |last3=Chauhan |first3=Surbhi |last4=Harit |first4=Saumya |date=2017 |title=MRI Evaluation of Size and Shape of Normal Pituitary Gland: Age and Sex Related Changes |journal=Journal of Clinical and Diagnostic Research |url=http://jcdr.net/article_fulltext.asp?issn=0973-709x&year=2017&volume=11&issue=12&page=TC01&issn=0973-709x&id=10933 |doi=10.7860/JCDR/2017/31034.10933|doi-access=free }}</ref> Its most common shape, found in 46% of people is flat, it is convex in 31.2% and concave in 22.8%.<ref name=":1" />

=== Anterior ===
{{Main|Anterior pituitary}}
The anterior pituitary lobe (adenohypophysis) arises from an [[evagination]] of the oral [[ectoderm]] ([[Rathke's pouch]]). This contrasts with the [[posterior pituitary]], which originates from [[neuroectoderm]].

[[Endocrine cell]]s of the anterior pituitary are controlled by regulatory hormones released by [[parvocellular neurosecretory cell]]s in the hypothalamic capillaries leading to infundibular blood vessels, which in turn lead to a second capillary bed in the anterior pituitary. This vascular relationship constitutes the [[hypophyseal portal system]]. Diffusing out of the second capillary bed, the hypothalamic [[releasing hormone]]s then bind to anterior pituitary endocrine cells, upregulating or downregulating their release of hormones.<ref name="Boron2009">{{cite book | last1=Boron | first1=Walter F. | last2=Boulpaep | first2=Emile L. | title=Medical Physiology | edition=2nd | publisher=Saunders Elsevier | location=Philadelphia | year=2009 | isbn=978-1-4160-3115-4 | pages=1016–1017}}</ref>

The anterior lobe of the pituitary can be divided into the [[pars tuberalis]] (pars infundibularis) and [[pars distalis]] (pars glandularis) that constitutes ~80% of the gland. The [[pars intermedia]] (the intermediate lobe) lies between the pars distalis and the pars tuberalis, and is rudimentary in the human, although in other species it is more developed.<ref name=":0" /> It develops from a depression in the dorsal wall of the [[pharynx]] (stomal part) known as Rathke's pouch.

The [[anterior pituitary]] contains several different types of cells that synthesize and secrete hormones.<ref>{{Cite book|title=Textbook of Medical Physiology|publisher=Elsevier Saunders}}</ref> Usually there is one type of cell for each major hormone formed in the anterior pituitary. At least five different cell types can be differentiated using various [[Staining|stain]]s.

{| class="wikitable"
! Hormone
! Other names
! Symbol(s)
! Structure
! Secretory cells
! Staining
! Target
! Effect
|-
| [[Adrenocorticotropic hormone]]
| Corticotropin
| ACTH
| [[Polypeptide]]
| [[Corticotrophs]]
| [[Anterior pituitary basophil|Basophil]]
| [[Adrenal gland]]
| Secretion of [[glucocorticoid]], [[mineralocorticoid]] and [[androgen]]s
|-
| [[Thyroid-stimulating hormone]]
| Thyrotropin
| TSH
| [[Glycoprotein]]
| [[Thyrotrophs]]
| [[Anterior pituitary basophil|Basophil]]
| [[Thyroid gland]]
| Secretion of [[thyroid hormone]]s
|-
| [[Follicle-stimulating hormone]]
| -
| FSH
| Glycoprotein
| [[Gonadotroph]]s
| [[Anterior pituitary basophil|Basophil]]
| [[Gonads]]
| Growth of [[reproductive system]]
|-
| [[Luteinizing hormone]]
| Lutropin
| LH, ICSH
| Glycoprotein
| [[Gonadotroph]]s
| [[Anterior pituitary basophil|Basophil]]
| [[Gonads]]
| [[Sex hormone]] production
|-
| [[Growth hormone]]
| Somatotropin
| GH, STH
| Polypeptide
| [[Somatotrophs]]
| [[Acidophil]]
| [[Liver]], [[adipose tissue]]
| Promotes growth; [[lipid]] and [[carbohydrate metabolism]]
|-
| [[Prolactin]]
| Lactotropin
| PRL
| Polypeptide
| [[Lactotroph]]s
| [[Acidophil]]
| [[Ovary|Ovaries]], [[mammary gland]]s, [[testes]], [[prostate]]
| Secretion of [[estrogen]]s/[[progesterone]]; [[lactation]]; [[spermatogenesis]]; [[prostatic hyperplasia]]
| [[Thyroid-stimulating hormone|TSH]] and [[ACTH]] secretion
|}
<ref>Malendowicz, L.K; Rucinski, M; Belloni, A.S; Ziolkowska, A; and Nussdorfer, G.C. (2007) Leptin and the regulation of the hypothalamic-pituitary-adrenal axis. Int Rev Cytol. 263: 63-102.</ref><ref>Sone, M. and Osamura, R.Y. (2001) Leptin and the pituitary. Pituitary. Jan-Apr; 4(1-2): 15-23.</ref>

=== Posterior ===
{{Main|Posterior pituitary}}
The [[posterior pituitary]] consists of the posterior lobe and the [[pituitary stalk]] (infundibulum) that connects it to the hypothalamus. It develops as an extension of the hypothalamus, from the floor of the [[third ventricle]]. The posterior pituitary hormones are synthesized by cell bodies in the [[hypothalamus]]. The [[magnocellular neurosecretory cell]]s, of the supraoptic and paraventricular nuclei located in the hypothalamus, project axons down the infundibulum to terminals in the posterior pituitary. This simple arrangement differs sharply from that of the adjacent anterior pituitary, which does not develop from the hypothalamus.

The release of pituitary hormones by both the anterior and posterior lobes is under the control of the [[hypothalamus]], albeit in different ways.<ref name="Boron2009" />

== Function ==
[[File:Pituiary gland - regulatory hormones.png|thumb|280px|[[Pituitary hormones]]]]

The anterior pituitary regulates several physiological processes by secreting hormones. This includes stress (by secreting [[Adrenocorticotropic hormone|ACTH]]), growth (by secreting [[Growth hormone|GH]]), reproduction (by secreting [[Follicle-stimulating hormone|FSH]] and [[Luteinizing hormone|LH]]), metabolism rate (by secreting [[Thyroid-stimulating hormone|TSH]]) and [[lactation]] (by secreting [[prolactin]]). The [[intermediate lobe]] synthesizes and secretes [[melanocyte-stimulating hormone]]. The [[posterior pituitary]] (or neurohypophysis) is a lobe of the gland that is functionally connected to the [[hypothalamus]] by the [[median eminence]] via a small tube called the [[pituitary stalk]] (also called the infundibular stalk or the infundibulum). It regulates hydroelectrolytic stability (by secreting [[Vasopressin|ADH]]), uterine contraction during labor and human attachment (by secreting [[oxytocin]]).

=== Anterior ===
The anterior pituitary synthesizes and secretes hormones. All '''releasing hormones''' (-RH) referred to can also be referred to as '''releasing factors''' (-RF).

[[Somatotropic cell|Somatotropes]]:
* [[Growth hormone]] (GH), also known as somatotropin, is released under the influence of hypothalamic [[growth hormone-releasing hormone]] (GHRH), and is [[Releasing and inhibiting hormones|inhibited]] by hypothalamic [[somatostatin]].

[[Corticotropic cell|Corticotropes]]:
* Cleaved from the precursor [[proopiomelanocortin]] protein, and include [[adrenocorticotropic hormone]] (ACTH), and [[beta-endorphin]], and [[melanocyte-stimulating hormone]] are released.<ref>{{Cite journal |last1=Dall’Olmo |first1=Luigi |last2=Papa |first2=Nicole |last3=Surdo |first3=Nicoletta Concetta |last4=Marigo |first4=Ilaria |last5=Mocellin |first5=Simone |date=2023-08-22 |title=Alpha-melanocyte stimulating hormone (α-MSH): biology, clinical relevance and implication in melanoma |journal=Journal of Translational Medicine |volume=21 |issue=1 |pages=562 |doi=10.1186/s12967-023-04405-y |doi-access=free |issn=1479-5876 |pmc=10463388 |pmid=37608347}}</ref>

[[Thyrotropic cell|Thyrotropes]]:
* [[Thyroid-stimulating hormone]] (TSH) is released under the influence of [[Hypothalamus|hypothalamic]] [[thyrotropin-releasing hormone]] (TRH) and is inhibited by somatostatin.

[[Gonadotropic cell|Gonadotropes]]:
* [[Luteinizing hormone]] (LH). stimulated by Gonadotropin-releasing hormone (GnRH) 
* [[Follicle-stimulating hormone]] (FSH), also stimulated by Gonadotropin-releasing Hormone (GnRH), and also by Activin

[[Lactotropic cell|Lactotropes]]:
* [[Prolactin]] (PRL), whose release is inconsistently stimulated by hypothalamic TRH, oxytocin, vasopressin, vasoactive intestinal peptide, angiotensin II, neuropeptide Y, galanin, substance P, bombesin-like peptides (gastrin-releasing peptide, neuromedin B and C), and neurotensin, and inhibited by hypothalamic dopamine.<ref name="Melmed2010">{{cite book|author=Shlomo Melmed|title=The pituitary|url=https://books.google.com/books?id=OFFW68kMpFIC&pg=PA40|date=3 December 2010|publisher=Academic Press|isbn=978-0-12-380926-1|page=40}}</ref>

These hormones are released from the anterior pituitary under the influence of the [[hypothalamus]]. Hypothalamic hormones are secreted to the anterior lobe by way of a special [[capillary]] system, called the [[Hypophyseal portal system|hypothalamic-hypophysial portal system]].

There is also a non-endocrine cell population called [[folliculostellate cell]]s.

=== Posterior ===
The posterior pituitary stores and secretes (but does not synthesize) the following important endocrine hormones:

[[Magnocellular neurosecretory cell|Magnocellular neurons]]:
* [[Antidiuretic hormone]] (ADH, also known as [[vasopressin]] and arginine vasopressin AVP), the majority of which is released from the [[supraoptic nucleus]] in the [[hypothalamus]].
* [[Oxytocin]], most of which is released from the [[paraventricular nucleus]] in the [[hypothalamus]]. Oxytocin is one of the few hormones to create a [[positive feedback]] loop. For example, uterine contractions stimulate the release of oxytocin from the posterior pituitary, which, in turn, increases uterine contractions. This positive feedback loop continues throughout labour.

=== Hormones ===
Hormones secreted from the pituitary gland help control the following body processes:
* [[Human development (biology)|Growth]] (GH)
* [[Blood pressure]]
* Some aspects of [[pregnancy]] and [[childbirth]] including stimulation of [[Uterine contraction#Childbirth|uterine contractions]]
* [[Lactation#Hormonal influences|Breast milk production]]
* [[Sex organ]] functions in both [[sex]]es
* [[Thyroid gland]] function
* [[Metabolism|Metabolic]] conversion of food into [[energy]]
* [[Water]] and [[osmolarity]] regulation in the body
* Water balance via the control of reabsorption of [[water]] by the [[kidneys]]
* Temperature regulation
* [[Pain]] relief

== Development ==
{{Section citations needed|date=November 2024}}
The development of the pituitary gland is a complex process that occurs early in the [[organogenesis]] stage of [[embryonic development]]. It begins as a thickening of cells 
in the embryonic [[ectoderm]] that form a [[neurogenic placode|neurogenic cranial placode]], the '''hypophyseal placode''' or '''adenohypophyseal placode''', that in the fourth week of [[gestational age]], gives rise to [[Rathke's pouch]].<ref name="Ilahi">{{cite web |last1=Ilahi |first1=Sadia |last2=Ilahi |first2=Tahir B. |title=Anatomy, Adenohypophysis (Pars Anterior, Anterior Pituitary) |url=https://www.ncbi.nlm.nih.gov/books/NBK519039/ |website=StatPearls |publisher=StatPearls Publishing |access-date=4 April 2025 |date=2025}}</ref> Rathke's pouch is the ectodermal outpocketing from the roof of the developing mouth, and gives rise to the anterior pituitary.<ref name="Scott">{{cite web |last1=Scott |first1=Ian S. |last2=Chattopadhyay |first2=Arpita |last3=Ansorge |first3=Olaf |title=Development and Microscopic Anatomy of the Pituitary Gland |url=https://www.ncbi.nlm.nih.gov/books/NBK425703/ |website=Endotext |publisher=MDText.com, Inc. |access-date=2 April 2025 |date=2000}}</ref>
A downward extension from the [[neuroectoderm]] as the infundibulum, forms the posterior pituitary.

[[Cellular differentiation|Differentiation]] and [[cell migration|migration]] takes place in weeks 5 and 6. Rathke's pouch grows towards the developing brain. The upper part of the pouch eventually constricts and detaches from the oral cavity, and cells in Rathke's pouch differentiate to form three parts of the adenohypophysis: the pars distalis, pars intermedia, and pars tuberalis.

In weeks 4 to 8 the posterior pituitary is formed. The infundibulum from the diencephalon elongates downward, forming a stalk that connects with Rathke’s pouch. This stalk will develop into the posterior pituitary where specialized cells from the hypothalamus, known as [[pituicyte]]s, migrate to help store and release hormones such as [[oxytocin]] and [[vasopressin]].

From week 12 to week 16, the anterior pituitary starts to produce hormones, notably [[growth hormone]] and around the 12th to 16th week of gestation, the anterior pituitary begins producing hormones like growth hormone (GH), and [[adrenocorticotropic hormone]] (ACTH), essential for fetal development.

By the end of the [[first trimester]] the pituitary gland is completely formed remaining connected to the hypothalamus by the pituitary stalk (infundibulum), allowing the integration of signals from the brain and regulation of various endocrine functions.
This dual-origin structure and function are what make the pituitary gland a unique and critical component of the endocrine system, acting as a bridge between the nervous and endocrine systems. 

Pituitary [[stem cell]]s can differentiate into different types of hormone-producing cells, with a great number specialising as [[gonadotrope]]s.<ref>{{Cite journal |last=Andoniadou |first=Cynthia Lilian |last2=Matsushima |first2=Danielle |last3=Mousavy Gharavy |first3=Seyedeh Neda |last4=Signore |first4=Massimo |last5=Mackintosh |first5=Albert Ian |last6=Schaeffer |first6=Marie |last7=Gaston-Massuet |first7=Carles |last8=Mollard |first8=Patrice |last9=Jacques |first9=Thomas Stanley |last10=Le Tissier |first10=Paul |last11=Dattani |first11=Mehul Tulsidas |last12=Pevny |first12=Larysa Halyna |last13=Martinez-Barbera |first13=Juan Pedro |date=October 2013 |title=Sox2+ Stem/Progenitor Cells in the Adult Mouse Pituitary Support Organ Homeostasis and Have Tumor-Inducing Potential |url=https://linkinghub.elsevier.com/retrieve/pii/S1934590913003123 |journal=Cell Stem Cell |language=en |volume=13 |issue=4 |pages=433–445 |doi=10.1016/j.stem.2013.07.004|doi-access=free }}</ref><ref>{{Cite journal |last=Pérez Millán |first=María Inés |last2=Cheung |first2=Leonard Y. M. |last3=Mercogliano |first3=Florencia |last4=Camilletti |first4=Maria Andrea |last5=Chirino Felker |first5=Gonzalo T. |last6=Moro |first6=Lucia N. |last7=Miriuka |first7=Santiago |last8=Brinkmeier |first8=Michelle L. |last9=Camper |first9=Sally A. |date=February 2024 |title=Pituitary stem cells: past, present and future perspectives |url=https://www.nature.com/articles/s41574-023-00922-4 |journal=Nature Reviews Endocrinology |language=en |volume=20 |issue=2 |pages=77–92 |doi=10.1038/s41574-023-00922-4 |issn=1759-5029 |pmc=10964491 |pmid=38102391}}</ref><ref>{{Cite journal |last=Rizzoti |first=Karine |last2=Akiyama |first2=Haruhiko |last3=Lovell-Badge |first3=Robin |date=October 2013 |title=Mobilized Adult Pituitary Stem Cells Contribute to Endocrine Regeneration in Response to Physiological Demand |url=https://linkinghub.elsevier.com/retrieve/pii/S1934590913003147 |journal=Cell Stem Cell |language=en |volume=13 |issue=4 |pages=419–432 |doi=10.1016/j.stem.2013.07.006 |pmc=3793864 |pmid=24094323}}</ref><ref>{{Citation |last=Sheridan |first=Daniel |title=Gonadotrophs have a dual origin, with most derived from pituitary stem cells during minipuberty |date=2024-09-09 |url=http://biorxiv.org/lookup/doi/10.1101/2024.09.09.610834 |access-date=2024-12-06 |language=en |doi=10.1101/2024.09.09.610834 |last2=Chakravarty |first2=Probir |last3=Golan |first3=Gil |last4=Shiakola |first4=Yolanda |last5=Olsen |first5=Jessica |last6=Burnett |first6=Elise |last7=Galichet |first7=Christophe |last8=Mollard |first8=Patrice |last9=Melamed |first9=Philippa}}</ref>

== Clinical significance ==
{{Main|Pituitary disease}}
[[File:Acromegaly hands.JPEG|thumb|Normal-sized hand (left) and enlarged hand caused by [[acromegaly]] (right)]]

Some of the diseases involving the pituitary gland are:
* [[Central diabetes insipidus]] caused by a deficiency of [[vasopressin]]
* [[Gigantism]] and [[acromegaly]] caused by an excess of growth hormone in childhood and adult, respectively
* [[Hypothyroidism]] caused by a deficiency of [[thyroid-stimulating hormone]]
* [[Hyperpituitarism]], the increased (hyper) secretion of one or more of the hormones normally produced by the pituitary gland
* [[Hypopituitarism]], the decreased (hypo) secretion of one or more of the hormones normally produced by the pituitary gland
* [[Pituitary adenoma]]s, mostly [[benign tumor]]s of the pituitary gland

All of the functions of the pituitary gland can be adversely affected by an over- or under-production of associated hormones.

The pituitary gland is important for mediating the stress response, via the [[hypothalamic–pituitary–adrenal axis]] (HPA axis). Critically, pituitary gland growth during adolescence can be altered by early life stress such as childhood maltreatment or maternal dysphoric (depressive) behavior.<ref>{{Cite journal |title=Early life stress alters pituitary growth during adolescence—A longitudinal study |url=http://www.psyneuen-journal.com/article/S0306-4530%252815%252900019-0/abstract |journal=Psychoneuroendocrinology |pages=185–194 |volume=53 |doi=10.1016/j.psyneuen.2015.01.005 |first1=Despina E. |last1=Ganella |first2=Nicholas B. |last2=Allen |first3=Julian G. |last3=Simmons |first4=Orli |last4=Schwartz |first5=Jee Hyun |last5=Kim |first6=Lisa |last6=Sheeber |first7=Sarah |last7=Whittle |pmid=25622011 |year=2015 |hdl=10536/DRO/DU:30144589 |s2cid=5247274|url-access=subscription }}</ref>

It has been demonstrated that, after controlling for age, sex, and BMI, larger quantities of [[DHEA]] and [[DHEA-S]] tended to be linked to larger pituitary volume.<ref name="ReferenceA">{{cite journal |last1=Murray |first1=CR |last2=Simmons |first2=JG |last3=Allen |first3=NB |last4=Byrne |first4=ML |last5=Mundy |first5=LK |last6=Seal |first6=ML |last7=Patton |first7=GC |last8=Olsson |first8=CA |last9=Whittle |first9=S |title=Associations between dehydroepiandrosterone (DHEA) levels, pituitary volume, and social anxiety in children |journal=Psychoneuroendocrinology |date=February 2016 |volume=64 |pages=31–9 |pmid=26600008 |doi=10.1016/j.psyneuen.2015.11.004 |s2cid=22520320}}</ref> Additionally, a correlation between pituitary gland volume and [[social anxiety]] subscale scores was identified which provided a basis for exploring mediation. Again controlling for age, sex, and BMI, [[DHEA]] and [[DHEA-S]] have been found to be predictive of larger pituitary gland volume, which was also associated with increased ratings of social anxiety.<ref name="ReferenceA"/> This research provides evidence that pituitary gland volume mediates the link between higher DHEA(S) levels (associated with relatively early adrenarche) and traits associated with social anxiety.<ref name="ReferenceA"/> Children who experience early adrenarcheal development tend to have larger pituitary gland volume compared to children with later adrenarcheal development.<ref name="ReferenceA"/>

== History ==

=== Etymology ===
{{Wiktionary|pituitary gland|hypophysis}}

==== Pituitary gland ====
The Greek [[physician]] [[Galen]] referred to the pituitary gland by only using the ([[Ancient Greek]]) name {{Lang|grc|ἀδήν}},<ref name="Hyrtl1880">Hyrtl, J. (1880). ''Onomatologia Anatomica. Geschichte und Kritik der anatomischen Sprache der Gegenwart.'' Wien: Wilhelm Braumüller. K.K. Hof- und Universitätsbuchhändler.</ref> ''gland''.<ref name="Liddell & Scott">Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press.</ref> He described the pituitary gland as part of a series of secretory organs for the excretion of [[nasal mucus]].<ref name="Hyrtl1880"/> Anatomist [[Andreas Vesalius]] translated {{Lang|grc|ἀδήν}} with ''glans, in quam pituita destillat'', "gland in which slime (''pituita''<ref name="Lewis & Short">Lewis, C.T. & Short, C. (1879). ''A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary.'' Oxford: Clarendon Press.</ref>) drips".<ref name="Hyrtl1880"/><ref name="Schreger">Schreger, C.H.Th.(1805). ''Synonymia anatomica. Synonymik der anatomischen Nomenclatur.'' Fürth: im Bureau für Literatur.</ref> Besides this 'descriptive' name, Vesalius used ''glandula pituitaria'', from which the English name ''pituitary gland''<ref name="Dorland">Anderson, D.M. (2000). ''Dorland's illustrated medical dictionary'' (29th edition). Philadelphia/London/Toronto/Montreal/Sydney/Tokyo: W.B. Saunders Company.</ref> is ultimately derived.

The expression ''glandula pituitaria'' is still used as official synonym beside ''hypophysis'' in the official Latin nomenclature ''[[Terminologia Anatomica]]''.<ref name="FCAT">Federative Committee on Anatomical Terminology (FCAT) (1998). ''Terminologia Anatomica''. Stuttgart: Thieme</ref> In the seventeenth century the supposed function of the pituitary gland to produce nasal mucus was debunked.<ref name="Hyrtl1880"/> The expression ''glandula pituitaria'' and its English equivalent ''pituitary gland'' can only be justified from a historical point of view.<ref name="Triepel1927">Triepel, H. (1927). ''Die anatomischen Namen. Ihre Ableitung und Aussprache. Anhang: Biographische Notizen.''(Elfte Auflage). München: Verlag J.F. Bergmann.</ref> The inclusion of this synonym is merely justified by noting that the main term ''hypophysis'' is a much less popular term.<ref name="NA3-62">International Anatomical Nomenclature Committee (1966). ''Nomina Anatomica''. Amsterdam: Excerpta Medica Foundation, p. 62</ref>

==== Hypophysis ====
{{Anchor|Hypophysial|Hypophyseal}}
Note: ''hypophysial'' (or ''hypophyseal'') means "related to the hypophysis (pituitary gland)".

The German anatomist [[Samuel Thomas von Sömmerring]] coined the name ''hypophysis''.<ref name="Hyrtl1880"/> This name consists<ref name="Hyrtl1880"/><ref name="Triepel1927"/> of ὑπό ('under')<ref name="Liddell & Scott"/> and φύειν ('to grow').<ref name="Liddell & Scott"/> In later Greek ὑπόφυσις is used differently by Greek physicians as ''outgrowth''.<ref name="Hyrtl1880"/> Sömmering also used the equivalent expression ''appendix cerebri'',<ref name="Hyrtl1880"/><ref name="Schreger"/> with ''appendix'' as ''appendage''.<ref name="Lewis & Short"/> In various languages, {{Lang|de|Hirnanhang}}<ref name="Schreger"/> in [[German language|German]] and {{Lang|nl|hersenaanhangsel}}<ref name="Pinkhof1923">Pinkhof, H. (1923). ''Vertalend en verklarend woordenboek van uitheemsche geneeskundige termen.'' Haarlem: De Erven F. Bohn.</ref> in [[Dutch language|Dutch]], the terms are derived from ''appendix cerebri''.

==Other animals==
The pituitary gland is found in all vertebrates, but its structure varies among different groups.

The division of the pituitary described above is typical of [[mammal]]s, and is also true, to varying degrees, of all [[tetrapod]]s. However, only in mammals does the posterior pituitary have a compact shape. In [[lungfish]], it is a relatively flat sheet of tissue lying above the anterior pituitary, but in [[amphibian]]s, [[reptile]]s, and [[bird]]s, it becomes increasingly well developed. The intermediate lobe is, in general, not well developed in any species and is entirely absent in birds.<ref name="VB" />

The structure of the pituitary in fish, apart from the lungfish, is generally different from that in other animals. In general, the intermediate lobe tends to be well developed, and may equal the remainder of the anterior pituitary in size. The posterior lobe typically forms a sheet of tissue at the base of the pituitary stalk, and in most cases sends irregular finger-like projection into the tissue of the anterior pituitary, which lies directly beneath it. The anterior pituitary is typically divided into two regions, a more anterior ''rostral'' portion and a posterior ''proximal'' portion, but the boundary between the two is often not clearly marked. In [[elasmobranch]]s, there is an additional, ''ventral lobe'' beneath the anterior pituitary proper.<ref name="VB"/>

The arrangement in [[lamprey]]s, which are among the most primitive of all fish, may indicate how the pituitary originally evolved in ancestral vertebrates. Here, the posterior pituitary is a simple flat sheet of tissue at the base of the brain, and there is no pituitary stalk. Rathke's pouch remains open to the outside, close to the nasal openings. Closely associated with the pouch are three distinct clusters of glandular tissue, corresponding to the intermediate lobe, and the rostral and proximal portions of the anterior pituitary. These various parts are separated by [[meninges|meningial]] membranes, suggesting that the pituitary of other vertebrates may have formed from the fusion of a pair of separate, but associated, glands.<ref name="VB"/>

Most [[armadillos]] also possess a neural secretory gland very similar in form to the posterior pituitary, but located in the tail and associated with the [[spinal cord]]. This may have a function in [[osmoregulation]].<ref name="VB"/>

There is a structure [[Homology (biology)|analogous]] to the pituitary in the [[octopus]] brain.<ref>{{cite journal |last1=Wells |first1=M. J. |last2=Wells |first2=J. |year=1969 |title=Pituitary Analogue in the Octopus |journal=[[Nature (journal)|Nature]] |volume=222 |issue=5190 |pages=293–294 |doi=10.1038/222293a0 |pmid=5778406 |bibcode=1969Natur.222..293W |s2cid=4159935 }}</ref>

=== Intermediate lobe ===
Although rudimentary in humans (and often considered part of the [[anterior pituitary]]), the [[Pars intermedia|intermediate lobe]] located between the anterior and posterior pituitary is important to many animals. For instance, in fish, it is believed to control physiological color change. In adult humans, it is just a thin layer of cells between the anterior and posterior pituitary. The intermediate lobe produces [[melanocyte-stimulating hormone]] (MSH), although this function is often (imprecisely) attributed to the anterior pituitary.{{fact|date=September 2024}}

The intermediate lobe is, in general, not well developed in tetrapods, and is entirely absent in birds.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 549–550|isbn= 0-03-910284-X}}</ref>

==Additional images==
<gallery>
Image:Diagram showing the position of the pituitary gland in the brain CRUK 413.svg|Frontal view
Image:Illu pituitary pineal glands.jpg|Pituitary and pineal glands
Image:Gray1180.png|Depiction of pituitary gland
</gallery>

== See also ==
* [[Head and neck anatomy]]
* [[Chromophobe cell]]
:* [[Melanotroph]]
* [[Chromophil]]
:* [[Acidophil cell]]
:* [[Basophil cell]]
* [[Oxyphil cell (parathyroid)]]
* [[Neuroendocrine cell]]

== References ==
{{reflist|30em}}

== External links ==
{{wiktionary|pituitary gland|hypophysis}}
{{Commons category}}
* {{BrainInfo|hier|382}}
* {{BUHistology|14201loa}}
* [https://web.archive.org/web/20111125135906/http://www.umm.edu/endocrin/pitgland.htm The Pituitary Gland, from the UMM Endocrinology Health Guide] (2011 archive)
* [https://web.archive.org/web/20090212095614/http://instruction.cvhs.okstate.edu/Histology/HistologyReference/HREndoframe.htm Oklahoma State, Endocrine System]
* [https://www.pituitary.org.uk/ The Pituitary Foundation]
* [http://www.pituitary.org The Pituitary Network Association -- pituitary.org]

{{System and organs}}
{{endocrine system}}
{{Diencephalon}}
{{Authority control}}

[[Category:Pituitary gland| ]]
[[Category:Endocrine system anatomy]]
[[Category:Human head and neck]]
[[Category:Neuroendocrinology]]
[[Category:Human female endocrine system]]
[[Category:Articles containing video clips]]