Genital - Male Development
|Embryology - 17 Feb 2018 Expand to Translate|
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- 1 Introduction
- 2 Some Recent Findings
- 3 Textbooks
- 4 Movies
- 5 Development Overview
- 6 Gonad - Testis
- 7 Internal Genital
- 8 External Genital
- 9 Hormones
- 10 Additional Images
- 11 References
- 12 Terms
- 13 Glossary Links
The male and female reproductive systems develop initially "indifferently", it is the product of the Y chromosome SRY gene that makes the "difference". The mesonephric duct (Wolffian Duct) contributes the majority of male internal genital tract.
Embryonic gonad development leads to the mesonephric/paramesonephric duct changes, while the external genitaila remain indeterminate in appearance through to the fetal period.
Importantly its sex chromosome dependence, late embryonic/fetal differential development, complex morphogenic changes, long time-course, hormonal sensitivity and hormonal influences make it a system prone to many different abnormalities.
Some Recent Findings
|More recent papers|
This table shows an automated computer PubMed search using the listed sub-heading term.
References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.
Hussein Nasser, Michael King, Henrietta Kotlus Rosenberg, Ally Rosen, Eric Wilck, William L Simpson Anatomy and pathology of the canal of Nuck. Clin Imaging: 2018, 51;83-92 PubMed 29448124
Pasqualino Loi, Cesare Galli, Giovanna Lazzari, Kazutsugu Matsukawa, Josef Fulka Jr, Frank Goeritz, Thomas B Hildebrandt Development to term of sheep embryos reconstructed after inner cell mass/trophoblast exchange. J. Reprod. Dev.: 2018; PubMed 29445070
H Kaya, B Polat, A Albayrak, T Mercantepe, B Buyuk Protective effect of an L-type calcium channel blocker, amlodipine, on paracetamol-induced hepatotoxicity in rats. Hum Exp Toxicol: 2018;960327118758382 PubMed 29441826
Sonja Zafirovic, Emina Sudar-Milovanovic, Milan Obradovic, Jelena Djordjevic, Nebojsa Jasnic, Milica Labudovic Borovic, Esma R Isenovic Involvement of PI3K, Akt, and RhoA in oestradiol regulation of cardiac iNOS expression. Curr Vasc Pharmacol: 2018; PubMed 29437011
Piotr Celichowski, Karol Jopek, Paulina Milecka, Marta Szyszka, Marianna Tyczewska, Ludwik K Malendowicz, Marcin Ruciński Nicotinamide phosphoribosyltransferase and the hypothalamic-pituitary-adrenal axis of the rat. Mol Med Rep: 2018; PubMed 29436637
- Human Embryology (2nd ed.) Larson Chapter 10 p261-306
- The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapter 13 p303-346
- Before We Are Born (5th ed.) Moore and Persaud Chapter 14 p289-326
- Essentials of Human Embryology, Larson Chapter 10 p173-205
- Human Embryology, Fitzgerald and Fitzgerald Chapter 21-22 p134-152
- Developmental Biology (6th ed.) Gilbert Chapter 14 Intermediate Mesoderm
|Mouse Primordial Germ Cell Migration|
Three main stages during development, mesonephric/paramesonephric duct changes are one of the first male/female differences that occur in development, while external genitaila remain indeterminate in appearance for quite a while.
- Differentiation of gonad (Sex determination)
- Differentiation of internal genital organs
- Differentiation of external genital organs
The 2nd and 3rd stages dependent on endocrine gonad. Reproductive development has a long maturation timecourse, begining in the embryo and finishing in puberty. (More? Puberty Development)
Historic Images of Genital Changes
|Urogenital indifferent||Urogenital male||Urogenital female|
Gonad - Testis
See the detailed notes on testis development.
- Links: Testis Development
Mesonephric duct or Wolffian duct differentiates to form the male internal genital tract the vas deferens (ductus deferens, vas deferens or simply vas). Associated with the duct are the male prostate and accessory glands.
|Human Mesonephric Duct position (week 6 to 11)|
| Schematic representations of the descent of the mesonephric duct (Wolffian duct, WD) or vas deferens. Anterior view.
|Adult Ductus deferens|
|Human prostate histology||Corpora Amylacea||Submucosal gland|
|(adult, low power overview)||(adult, detail)||(adult, high power detail)|
- external genitalia are initially identical and undergo male and female differentiation under the influence or absence of steroidal sex hormones.
- Indifferent stage ‐ cloaca divided by proliferating mesenchyme forming the urorectal septum which separates the ventral urogenital sinus from the dorsal rectum.
- Difference stage ‐ locally in this region the presence or absence of dihydrotestosterone (DHT), generated from testosterone, determines male/female development.
Anti-Müllerian Hormone (AMH, Müllerian Inhibiting Substance, MIS, Müllerian Inhibiting Factor, MIF) is a secreted glycoprotein factor of the transforming growth factor-beta, TGF-beta superfamily, that regulates gonadal and genital tract development.
In the male embryo, the Sertoli cell secrete AMH and inhibit paramesonephric (Mullerian) duct development. This secreted hormone also acts to differentiate the Leydig cells (interstitial cells).
In postnatal males, AMH increases during the first month, reaching peak level at 6 months of age, and then slowly declines during childhood falling to low levels in puberty. In reproductive age women, AMH is produced in the ovary by the granulosa cells surrounding preantral and small antral follicles and serum levels may reflect the remaining follicle cohort and decrease with age.
Sertoli cells release mainly a prohormone (proAMH), that is cleaved by subtilisin/kexin-type proprotein convertases or serine proteinases. The cleaved protein forms a stable complex (AMHN,C). Therefore the circulating AMH is a mixture of proAMH and AMHN,C. It has been suggested that proAMH may be activated within the gonads and also by its endocrine target-cells.
Male testosterone and AMH levels
During ovary follicle development, the granulosa cells secrete AMH and it may have a role in follicular recruitment and development. and may also function in postnatal elevation of FSH secretion in females.
Other AMH Tissues
- The placenta has also been shown to both synthesise AMH and express its receptors.
- AMH receptors have been identified in both the pituitary and brain.
| Male presence of Dihydrotestosterone (DHT, 5α-dihydrotestosterone, androstanolone, 5α-androstan-17β-ol-3-one).
Androgen and Digit ratio (2D:4D)
The ratio of 2nd and 4th finger (D, digit) length. This ratio has been suggested to relate to high fetal testosterone concentration (males have lower 2D:4D than females) and has been shown for several species. Although a study in mice has not shown the same correlation. There have been some suggestions that the ratio may also be an indicator of various neurological abnormalities.
To measure (2D:4D) - using your right hand palm up, measure the index finger (2) and ring finger (4) length from palm to tip. Dividing the index finger by the ring finger gives the 2D:4D ratio, average women ratio is 1, average men is 0.98.
- Marissa L Gredler, Ashley W Seifert, Martin J Cohn Tissue-specific roles of Fgfr2 in development of the external genitalia. Development: 2015, 142(12);2203-12 PubMed 26081573
- S F Nemec, U Nemec, M Weber, P C Brugger, D Bettelheim, S Rotmensch, C R Krestan, D L Rimoin, J M Graham, D Prayer Penile biometry on prenatal magnetic resonance imaging. Ultrasound Obstet Gynecol: 2012, 39(3);330-5 PubMed 21484906
- Simone Funke, Edina Flach, István Kiss, János Sándor, Gabriella Vida, József Bódis, Tibor Ertl Male reproductive tract abnormalities: more common after assisted reproduction? Early Hum. Dev.: 2010, 86(9);547-50 PubMed 20674196
- Congxing Lin, Yan Yin, G Michael Veith, Alexander V Fisher, Fanxin Long, Liang Ma Temporal and spatial dissection of Shh signaling in genital tubercle development. Development: 2009, 136(23);3959-67 PubMed 19906863
- Xinyu Wu, Christopher Ferrara, Ellen Shapiro, Irina Grishina Bmp7 expression and null phenotype in the urogenital system suggest a role in re-organization of the urethral epithelium. Gene Expr. Patterns: 2009, 9(4);224-30 PubMed 19159697
- Zhe Wu Jin, Hiroshi Abe, Nobuyuki Hinata, Xiang Wu Li, Gen Murakami, José Francisco Rodríguez-Vázquez Descent of mesonephric duct to the final position of the vas deferens in human embryo and fetus. Anat Cell Biol: 2016, 49(4);231-240 PubMed 28127497
- Ian S McLennan, Michael W Pankhurst Anti-Müllerian hormone is a gonadal cytokine with two circulating forms and cryptic actions. J. Endocrinol.: 2015; PubMed 26163524
- Ghislaine Garrel, Chrystèle Racine, David L'Hôte, Chantal Denoyelle, Céline J Guigon, Nathalie di Clemente, Joëlle Cohen-Tannoudji Anti-Müllerian hormone: a new actor of sexual dimorphism in pituitary gonadotrope activity before puberty. Sci Rep: 2016, 6;23790 PubMed 27030385
- R Novembri, L Funghi, C Voltolini, G Belmonte, S Vannuccini, M Torricelli, F Petraglia Placenta expresses anti-Müllerian hormone and its receptor: Sex-related difference in fetal membranes. Placenta: 2015; PubMed 25972076
- Matthew H McIntyre The use of digit ratios as markers for perinatal androgen action. Reprod. Biol. Endocrinol.: 2006, 4;10 PubMed 16504142
- Reginia H Y Yan, Mark Bunning, Douglas Wahlsten, Peter L Hurd Digit ratio (2Dratio4D) differences between 20 strains of inbred mice. PLoS ONE: 2009, 4(6);e5801 PubMed 19495421
Martin J Cohn Development of the external genitalia: conserved and divergent mechanisms of appendage patterning. Dev. Dyn.: 2011, 240(5);1108-15 PubMed 21465625
Christian Larney, Timothy L Bailey, Peter Koopman Switching on sex: transcriptional regulation of the testis-determining gene Sry. Development: 2014, 141(11);2195-205 PubMed 24866114
Rodolfo A Rey, Romina P Grinspon Normal male sexual differentiation and aetiology of disorders of sex development. Best Pract. Res. Clin. Endocrinol. Metab.: 2011, 25(2);221-38 PubMed 21397195
Anna Biason-Lauber Control of sex development. Best Pract. Res. Clin. Endocrinol. Metab.: 2010, 24(2);163-86 PubMed 20541146
P Koopman The delicate balance between male and female sex determining pathways: potential for disruption of early steps in sexual development. Int. J. Androl.: 2010, 33(2);252-8 PubMed 19845801
Dagmar Wilhelm, Stephen Palmer, Peter Koopman Sex determination and gonadal development in mammals. Physiol. Rev.: 2007, 87(1);1-28 PubMed 17237341
Richard M Sharpe Pathways of endocrine disruption during male sexual differentiation and masculinization. Best Pract. Res. Clin. Endocrinol. Metab.: 2006, 20(1);91-110 PubMed 16522522
Garry L Warne, Shankar Kanumakala Molecular endocrinology of sex differentiation. Semin. Reprod. Med.: 2002, 20(3);169-80 PubMed 12428197
I M Adham, J M Emmen, W Engel The role of the testicular factor INSL3 in establishing the gonadal position. Mol. Cell. Endocrinol.: 2000, 160(1-2);11-6 PubMed 10715534
O Hiort, P M Holterhus The molecular basis of male sexual differentiation. Eur. J. Endocrinol.: 2000, 142(2);101-10 PubMed 10664515
Kallayanee Chawengsaksophak, Terje Svingen, Ee Ting Ng, Trevor Epp, Cassy M Spiller, Charlotte Clark, Helen Cooper, Peter Koopman Loss of Wnt5a disrupts primordial germ cell migration and male sexual development in mice. Biol. Reprod.: 2012, 86(1);1-12 PubMed 21900680
M Cools, K P Wolffenbuttel, S L S Drop, J W Oosterhuis, L H J Looijenga Gonadal development and tumor formation at the crossroads of male and female sex determination. Sex Dev: 2011, 5(4);167-80 PubMed 21791949
- mesonephric duct - (Wollfian duct) An early developing urogenital paired duct system that initially runs the length of the embryo, that will differentiate and form the male reproductive duct system (ductus deferens). In females, this duct degenerates occasionally some remnants may remain associated in broad ligament.
- Wolffian duct - (mesonephric duct, preferred terminology), A developmental duct that runs from the mesonephros to cloaca. The duct in male differentiates to form the ductus deferens and in female the same structure regresses. Historically named after Caspar Friedrich Wolff (1733-1794), a German scientist and early embryology researcher and is said to have established the doctrine of germ layers. (More? Caspar Friedrich Wolff)
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Cite this page: Hill, M.A. (2018, February 17) Embryology Genital - Male Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Genital_-_Male_Development
- © Dr Mark Hill 2018, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G