Endocrine - Hypothalamus Development: Difference between revisions

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In the early embryo, neuroectoderm of the forebrain (prosenecephalon) primary brain vesicle divides to form two secondary brain vesicles, telencephalon (endbrain, cortex) and diencephalon. The historic description is that the diencephalon ventro-lateral wall, intermediate zone proliferation generates the primordial hypothalamus. A recent "Prosomeric model'''<ref name="PMID25852489"><pubmed>21559484</pubmed></ref> based on gene expression in the mouse suggests an overall different origin of the hypothalamus arising from the telencephalon.
In the early embryo, neuroectoderm of the forebrain (prosenecephalon) primary brain vesicle divides to form two secondary brain vesicles, telencephalon (endbrain, cortex) and diencephalon. The historic description is that the diencephalon ventro-lateral wall, intermediate zone proliferation generates the primordial hypothalamus. A recent "Prosomeric model"<ref name="PMID7939711"><pubmed>7939711</pubmed></ref><ref name="PMID25852489"><pubmed>21559484</pubmed></ref>, based on gene expression in the mouse, suggests an overall different origin of the hypothalamus arising from the telencephalon.




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In the adult, large neurosecretory cells of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) project to the [[Endocrine_-_Pituitary_Development|neurohypophysis]] from the hypothalamus. Other key nuclei within the hypothalamus include the sexually dimorphic nucleus (SDN, intermediate nucleus, INAH-1), suprachiasmatic nucleus (SCN) and tuberal lateral nucleus (NTL).
In the adult, large neurosecretory cells of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) project to the [[Endocrine_-_Pituitary_Development|neurohypophysis]] from the hypothalamus. Other key nuclei within the hypothalamus include the sexually dimorphic nucleus (SDN, intermediate nucleus, INAH-1), suprachiasmatic nucleus (SCN) and tuberal lateral nucleus (NTL). Anatomically surrounded by the anterior commissure and lamina terminalis anteriorly, the mammillary bodies and midbrain posteriorly, and thalamus superiorly.
Anatomically surrounded by the anterior commissure and lamina terminalis anteriorly, the mammillary bodies and midbrain posteriorly, and thalamus superiorly.





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Introduction

Human embryonic hypothalamus (Stage 22)
Adult hypothalamus position

The hypothalamus has a key role in regulating the nearby pituitary and peripheral endocrine organ functions. This neural region therefore is associated with hormonally related behaviour (anger and sexual activity), homeostatic regulation (blood pressure, heart rate, appetite, and temperature) and functions that relate to both (puberty, reproductive cycles, and lactation).


In the early embryo, neuroectoderm of the forebrain (prosenecephalon) primary brain vesicle divides to form two secondary brain vesicles, telencephalon (endbrain, cortex) and diencephalon. The historic description is that the diencephalon ventro-lateral wall, intermediate zone proliferation generates the primordial hypothalamus. A recent "Prosomeric model"[1][2], based on gene expression in the mouse, suggests an overall different origin of the hypothalamus arising from the telencephalon.


Hypothalamus development also occurs differentially in male and female embryos, described as part of neural sexual dimorphism.


In the adult, large neurosecretory cells of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) project to the neurohypophysis from the hypothalamus. Other key nuclei within the hypothalamus include the sexually dimorphic nucleus (SDN, intermediate nucleus, INAH-1), suprachiasmatic nucleus (SCN) and tuberal lateral nucleus (NTL). Anatomically surrounded by the anterior commissure and lamina terminalis anteriorly, the mammillary bodies and midbrain posteriorly, and thalamus superiorly.


Endocrine Links: Introduction | BGD Lecture | Science Lecture | Lecture Movie | pineal | hypothalamus‎ | pituitary | thyroid | parathyroid | thymus | pancreas | adrenal | endocrine gonad‎ | endocrine placenta | other tissues | Stage 22 | endocrine abnormalities | Hormones | Category:Endocrine
Historic Embryology - Endocrine  
1903 Islets of Langerhans | 1903 Pig Adrenal | 1904 interstitial Cells | 1908 Pancreas Different Species | 1908 Pituitary | 1908 Pituitary histology | 1911 Rathke's pouch | 1912 Suprarenal Bodies | 1914 Suprarenal Organs | 1915 Pharynx | 1916 Thyroid | 1918 Rabbit Hypophysis | 1920 Adrenal | 1935 Mammalian Hypophysis | 1926 Human Hypophysis | 1927 Adrenal | 1927 Hypophyseal fossa | 1930 Adrenal | 1932 Pineal Gland and Cysts | 1935 Hypophysis | 1935 Pineal | 1937 Pineal | 1935 Parathyroid | 1940 Adrenal | 1941 Thyroid | 1950 Thyroid Parathyroid Thymus | 1957 Adrenal

| Category:Hypothalamus | Lecture - Ectoderm Development | Lecture - Neural Development | Lecture - Head Development

Some Recent Findings

Adult mouse brain - prosomeric model
Adult mouse brain - prosomeric model[2]
  • A new scenario of hypothalamic organization: rationale of new hypotheses introduced in the updated prosomeric model[2] In this essay, we aim to explore in depth the new concept of the hypothalamus that was presented in the updated prosomeric model. Initial sections deal with the antecedents of prosomeric ideas represented by the extensive literature centered on the alternative columnar model of Herrick (1910), Kuhlenbeck (1973) and Swanson (1992, 2003); a detailed critique explores why the columnar model is not helpful in the search for causal developmental explanations. In contrast, the emerging prosomeric scenario visibly includes many possibilities to propose causal explanations of hypothalamic structure relative to both anteroposterior and dorsoventral patterning mechanisms, and insures the possibility to compare hypothalamic histogenesis with that of more caudal parts of the brain. Next the four major changes introduced in the organization of the hypothalamus on occasion of the updated model are presented, and our rationale for these changes is explored in detail. It is hoped that this example of morphological theoretical analysis may be useful for readers interested in brain models, or in understanding why models may need to change in the quest for higher consistency." (See also editorial[3])
  • Neuropeptide Signaling Differentially Affects Phase Maintenance and Rhythm Generation in SCN and Extra-SCN Circadian Oscillators[4] "Circadian rhythms in physiology and behavior are coordinated by the brain's dominant circadian pacemaker located in the suprachiasmatic nuclei (SCN) of the hypothalamus. Vasoactive intestinal polypeptide (VIP) and its receptor, VPAC(2), play important roles in the functioning of the SCN pacemaker. ... Further, our data indicate a link between circadian rhythm strength and the ability of tissues to resist circadian phase resetting."
  • Embryonic gonadotropin-releasing hormone signaling is necessary for maturation of the male reproductive axis.[5] "Surprisingly, genetic ablation (in mice) of GnRHR expressing cells significantly increased the number of GnRH neurons in the anterior hypothalamus, suggesting an unexpected role of GnRH signaling in establishing the size of the GnRH neuronal population.
More recent papers
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Search term: Hypothalamus Embryology

<pubmed limit=5>Hypothalamus Embryology</pubmed>

Hypothalamus Endocrine Axes

HPG Axis

Hypothalamus - Pituitary - Gonad endocrine axis.

XXhpgaxis.jpg This cartoon shows the Hypothalamus - Pituitary - Gonad (female) endocrine axis.

The arrows indicate how each of these endocrine organs interact and regulate each others secretions through endocrine feedback mechanisms.

Other Endocrine Axes

HPA axis.jpg

Hypothalamus - Pituitary - Adrenal endocrine axis.

HPT axis.jpg

Hypothalamus - Pituitary - Thyroid endocrine axis.

Development Overview

Stage 13 image 061.jpg Stage 22 image 055.jpg Gray0654.jpg
Diencephalon region, shown by optic stalk
(Stage 13)
Late embryonic hypothalamus
(Stage 22)
Early fetal human brain
(3 months, from a model by Wilhelm His)


  • Neuroectoderm - prosenecephalon then rostral diencephalon after induction by the underlying prechordal plate.
    • Sonic hedgehog (Shh) - initially expressed in prechordal plate, is essential for inductive process.
  • ventro-lateral wall intermediate zone proliferation
  • Mamillary bodies - form pea-sized swellings ventral wall of hypothalamus

Week 5

Secondary Brain Vesicles - Stage 13

Stage 13 serial labeled images
Stage 13 image 057.jpg Stage 13 image 058.jpg Stage 13 image 059.jpg Stage 13 image 060.jpg Stage 13 image 061.jpg Stage 13 image 062.jpg Stage 13 image 063.jpg
B1L B2L B3L B4L B5L B6L B7L

Week 8

Embryo Brain - Stage 22

Stage 22L serial labeled images
Stage 22 image 050.jpg Stage 22 image 051.jpg Stage 22 image 052.jpg Stage 22 image 053.jpg Stage 22 image 054.jpg Stage 22 image 055.jpg Stage 22 image 056.jpg
A1L A2L A3L A4L A5L A6L A7L
Stage 22 image 057.jpg Stage 22 image 058.jpg Stage 22 image 059.jpg Stage 22 image 060.jpg Stage 22 image 061.jpg Stage 22 image 062.jpg Stage 22 image 063.jpg
B1L B2L B3L B4L B5L B6L B7L

Week 10

Early Fetal Brain

10 Week Fetus head images
Human- fetal week 10 head A.jpg Human- fetal week 10 head B.jpg Human- fetal week 10 head C.jpg Human- fetal week 10 head D.jpg

Adult Hypothalamus Hormones

Adult human hypothalamus 02.jpg

Adult Human Hypothalamus[6]

Secreted hormone Abbreviation Produced by Effect
Thyrotropin-releasing hormone
(Prolactin-releasing hormone)
TRH, TRF, or PRH Parvocellular neurosecretory neurons thyroid-stimulating hormone (TSH) release from anterior pituitary (primarily)
Stimulate prolactin release from anterior pituitary
Dopamine
(Prolactin-inhibiting hormone)
DA or PIH Dopamine neurons of the arcuate nucleus Inhibit prolactin release from anterior pituitary
Growth hormone-releasing hormone GHRH Neuroendocrine neurons of the Arcuate nucleus Growth hormone (GH) release from anterior pituitary
Somatostatin
(growth hormone-inhibiting hormone)
SS, GHIH, or SRIF Neuroendocrine cells of the Periventricular nucleus Growth hormone (GH) release from anterior pituitary
Inhibit Thyroid-stimulating hormone|thyroid-stimulating hormone (TSH) release from anterior pituitary
Gonadotropin-releasing hormone GnRH or LHRH Neuroendocrine cells of the Preoptic area follicle-stimulating hormone (FSH) release from anterior pituitary
Stimulate Luteinizing hormone|luteinizing hormone (LH) release from anterior pituitary
Corticotropin-releasing hormone CRH or CRF Parvocellular neurosecretory neurons adrenocorticotropic hormone (ACTH) release from anterior pituitary
Oxytocin Magnocellular neurosecretory cells Lactation (letdown reflex)
Vasopressin
(antidiuretic hormone)
ADH or AVP Magnocellular neurosecretory neurons Increases water permeability in the distal convoluted tubule and collecting duct of nephrons, thus promoting water reabsorption and increasing blood volume

Hormones - Thyrotrophin releasing hormone (TRH), Corticotrophin releasing hormone (CRH), Arginine vasopressin (AVP), Gonadotrophin releasing hormone (GnRH), Growth hormone releasing hormone (GHRH), Somatostatin, Prolactin relasing factor (PRF), Dopamine


Growth hormone (GH) secretion from the pituitary is controlled in many different ways, including positive/negative regulation of synthesis and release by the hypothalamus. Hypothalamic GH releasing hormone (GHRH) activates and somatostatin suppresses growth hormone synthesis and release.

Hypothalamic Nuclei

Supraoptic Nucleus

(SON) Arginine vasopressin (AVP) and oxytocin (OT) synthesis and released in the posterior pituitary. These 2 hormones differ only in 2 amino acids in positions 3 and 8.

Arginine vasopressin (AVP) peptide hormone (9aa, nonapeptide)

  • synthesized as inactive preprohormone
  • regulates blood volume and pressure acting on the kidney and heart
  • Increased osmolality, due to blood volume reduction, increases AVP secretion.

Oxytocin (OT) peptide hormone (9aa, nonapeptide)

  • mainly produced in hypothalamic magnocellular neurons
  • regulates female reproductive pregnancy-associated changes (stimulation of milk ejection, uterine contractions)
  • acts on one type of OT receptor (OTR)
  • hormone is a non-glycosylated protein undergoes an initial cleavage by the convertase magnolysin (EC 3.4.24.62) to OT-Gly-Lys-Arg (OT-GKR).
  • additional processing produces other OT extended molecules: OT-Gly-Lys (OT-GK) and OT-Gly (OT-G, OT-X).
  • OT-G is converted by an α-amidating enzyme to C-amidated nonapeptide which is released into the circulation
  • may have a role in fetal heart growth[7] and in vascular tone, regrowth and remodeling.[8]


About Oxytocin Hormone
Structure Function
  • polypeptide hormone 9 amino acids
  • first peptide hormone to be sequenced and synthesized (1953).
  • single gene arose by duplication of vasopressin gene
    • vasopressin is 9 amino acid hormone constricts blood vessels and retain body water.
  • hormone degraded by GIT.
  • hormone cannot pass the blood-brain barrier.
  • Birth - increase in uterine muscle tone and strength of contractions.
  • Lactation - hormone released in response to the baby suckling.
  • stimulates contraction of muscle cells around mammary glands.
  • neural effects
Links: Birth | Hypothalamus | Endocrine | Mammary Gland | Milk | image - Oxytocin receptor pathways

Abnormalities: diabetes insipidus (vasopressin deficiency), syndrome of inappropriate antidiuresis (vasopressin excess)


Links: Birth | Search Bookshelf

Paraventricular Nucleus

Hypothalamus PVN and SCN
Oxytocin receptor pathways

(PVN) Arginine vasopressin (AVP) and oxytocin synthesis and released in the posterior pituitary. These 2 hormones differ only in 2 amino acids in positions 3 and 8.

  • magnocellular neurons
  • parvocellular neurosecretory neurons project axons to the pituitary median eminence
  • interneurons and neurons also project centrally

Arginine vasopressin (AVP) peptide hormone (9aa, nonapeptide)

  • synthesized as inactive preprohormone
  • regulates blood volume and pressure acting on the kidney and heart
  • Increased osmolality, due to blood volume reduction, increases AVP secretion.

Oxytocin (OT) peptide hormone (9aa, nonapeptide)

  • mainly produced in hypothalamic magnocellular neurons
  • regulates female reproductive pregnancy-associated changes
  • central effect on social and other behaviors, release from magnocellular dendrites and axonal projections of parvocellular neurons
  • acts on one type of OT receptor (OTR)
  • hormone is a non-glycosylated protein undergoes an initial cleavage by the convertase magnolysin (EC 3.4.24.62) to OT-Gly-Lys-Arg (OT-GKR).
  • additional processing produces other OT extended molecules: OT-Gly-Lys (OT-GK) and OT-Gly (OT-G, OT-X).
  • OT-G is converted by an α-amidating enzyme to C-amidated nonapeptide which is released into the circulation
  • may have a role in fetal heart growth[9]
Links: Birth | Search Bookshelf

Sexually Dimorphic Nucleus

(SDN, intermediate nucleus, INAH-1)

  • Twice as large in young male adults as in young females.
  • At birth 20% of the adult SDN cell number is present, from then until 2-4 years of age cell numbers increase equally rapidly in both sexes.
  • After this age cell numbers start to decrease in girls, creating the sex difference.

The SCN is the clock of the brain and shows circadian and seasonal fluctuations in vasopressin-expressing cell numbers. (SDN and SCN text modified from: Swaab, 1995)

Links: Search Bookshelf

Suprachiasmatic Nucleus

Hypothalamus PVN and SCN

(SCN) This nucleus is the clock of the brain and shows circadian and seasonal fluctuations in vasopressin-expressing cell numbers.

Links: Search Bookshelf

Tuberal Lateral Nucleus

Links: Search Bookshelf

(NTL) This nucleus is involved in feeding behavior and energy metabolism.

Tracts

  • retino-hypothalamus tract - (RHT)is the main connection between the eye and the hypothalamus, acts as a direct afferent pathway from the retina going through the optic chiasma.


Molecular

Transcription factor cascade (Sim1, Otp, Sim2, and Brn2) regulate differentiation of the anterior hypothalamus neuroendocrine cells.

Hypothalamus gene interaction model.jpg

Hypothalamus Development Gene Interaction Model[10]


Links: Notch

References

  1. <pubmed>7939711</pubmed>
  2. 2.0 2.1 2.2 <pubmed>21559484</pubmed>
  3. <pubmed>26157363</pubmed>
  4. <pubmed>21559484</pubmed>
  5. <pubmed>20805495</pubmed>
  6. <pubmed>23682342</pubmed>| PMC3654779 | Surg Neurol Int.
  7. <pubmed>15316117</pubmed>
  8. <pubmed>10811917</pubmed>
  9. <pubmed>15316117</pubmed>
  10. 24360028<pubmed>24360028</pubmed>| Neural Dev.

Reviews

<pubmed>24290347</pubmed> <pubmed>20626426</pubmed> <pubmed>12127306</pubmed>

Articles

<pubmed>20637232</pubmed> <pubmed>20628204</pubmed> <pubmed>15840737</pubmed>

Books

Endocrinology - An Integrated Approach Stephen Nussey and Saffron Whitehead St. George's Hospital Medical School, London, UK Oxford: BIOS Scientific Publishers; 2001. ISBN-10: 1-85996-252-1

Search PubMed

Search Pubmed: hypothalamus development

Additional Images

Terms

  • 3ß-diol - 5alpha-androstane-3beta, 17beta-diol
  • 3α-diol - 5alpha-androstane-3alpha, 17beta-diol
  • 5-HT - serotonin
  • 5αR - 5-alpha-reductase
  • ACTH - adrenocortcotropin releasing hormone
  • AR - androgen receptor
  • ARN - (AR) Arcuate nucleus
  • AVP - arginine vasopressin
  • BnST - bed nucleus of the stria terminalis
  • BSA - bovine serum albumin
  • CBP - CREB binding protein
  • CORT - corticosterone
  • CRE - cyclic adenosine monophosphate response element
  • CREB - CRE binding protein
  • CRF - corticotropin releasing factor
  • DES - diethylstilbesterol
  • DEX - dexamethasone
  • DHT - dihydrotestosterone
  • DMN - (DM) Dorsomedial hypothalamic nucleus
  • DPN - diarylproprionitrile
  • ER - estrogen receptor
  • ERE - estrogen response element
  • FSH - follicle stimulating hormone
  • FSL - flinders sensitive line
  • GABA - gamma-aminobutyric acid
  • GAS - general adaptation syndrome
  • GH - growth hormone
  • GLP-1 - glucagon-like peptide 1
  • GnRH - gonadotropin releasing hormone
  • GPER - G-protein coupled estrogen receptor
  • GR - glucocorticoid receptor
  • HPA - hypothalamo–pituitary–adrenal
  • HPG - hypothalamo–pituitary–gonadal
  • HRE - hormone respone element
  • HSD - hydroxysteroid dehydrogenase
  • ICV - intracerebroventricular
  • ir - immunoreactive
  • ISH - in situ hybridization
  • LH - luteinizing hormone
  • LHRH - luteinizing hormone releasing hormone
  • MPOA - medial preoptic area
  • MR - mineralocorticoid receptor
  • NTS - nucleus of the solitary tract
  • PPT - propylpyrazoletriol
  • PR - progesterone receptor
  • PVN - (PVA, PVH) Paraventricular nucleus
  • RAR - retinoic acid receptors
  • SCN - (SC) Suprachiasmatic nucleus
  • SON - (SO) Supraoptic nucleus
  • SRC - steroid receptor coactivators
  • T - testosterone
  • THR - thyroid hormone receptors
  • TPH - tryptophan hydroxylase
  • TRH - thyrotropin releasing hormone
  • TSH - thyroid stimulating hormone
  • VMN - (VM) Ventromedial nucleus


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Cite this page: Hill, M.A. (2024, March 29) Embryology Endocrine - Hypothalamus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Endocrine_-_Hypothalamus_Development

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