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Article: Sexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii

TitleSexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugenii
Authors
Issue Date1996
PublisherSpringer Verlag. The Journal's web site is located at http://link.springer.de/link/service/journals/00429/index.htm
Citation
Anatomy And Embryology, 1996, v. 194 n. 2, p. 111-134 How to Cite?
AbstractIn male tammar wallabies, the scrotum is the first organ to become sexually differentiated, 4-5 days before birth (day 22 of gestation). This is followed by enlargement of the gubernaculum and processus vaginalis one day before birth. However the indifferent gonad does not show any signs of testicular cord formation or androgen production until later, at around the time of birth; this is more pronounced at 2 days post-partum (p.p.), when the testis takes on a characteristic rounded appearance. Primordial germ cells proliferate throughout the testis at this time, although the testis does not become significantly heavier than the ovary until around 80 days p.p.. In females, the appearance of the mammary glands is the first sign of sexual differentiation 4-5 days before birth. The indifferent gonad first shows signs of developing an ovarian cortex and medulla 7 days after birth. The migrating germ cells are confined to the cortex, and first start to enter meiosis about 25 days after birth. The Wolffian (mesonephric) ducts are patent to the urogenital sinus in fetuses at day 21 of gestation. In the female they have started to regress by 10 days p.p. and only rudiments remain by day 25 p.p.. The Mullerian (paramesonephric) ducts develop adjacent to the cranial pole of the mesonephros at about day 25 of gestation and grow caudally to meet the urogenital sinus between days 2 and 7 p.p.. The Mullerian duct of the female develops a prominent ostium abdominale by day 9 p.p., but this structure has completely regressed in males by day 13 p.p.. The testis and ovary both migrate caudally, together with the adjacent mesonephros, at about day 10 p.p.. The ovaries remain around the level of lumbar vertebra 4 after about day 7 p.p., while the testes continue to descend. The testes enter the internal inguinal ring at about day 25 p.p., about the time that prostatic buds first appear in the urogenital sinus, and are in the inguinal canal from days 25 to 36 p.p.. They enter the scrotum at around day 36 p.p., and testicular descent is complete by days 65-72 p.p.. Melanin develops in the tunica vaginalis 72 days after birth. The overall development of the urogenital system in this marsupial is similar to that of eutherians but the sequence of events differs, with some aspects of genital differentiation preceding gonadal differentiation, apparently because they are directly controlled by X-linked genes, rather than indirectly controlled by gonadal steroids.
Persistent Identifierhttp://hdl.handle.net/10722/67695
ISSN
2008 Impact Factor: 1.39
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorRenfree, MBen_HK
dc.contributor.authorO, WSen_HK
dc.contributor.authorShort, RVen_HK
dc.contributor.authorShaw, Gen_HK
dc.date.accessioned2010-09-06T05:57:25Z-
dc.date.available2010-09-06T05:57:25Z-
dc.date.issued1996en_HK
dc.identifier.citationAnatomy And Embryology, 1996, v. 194 n. 2, p. 111-134en_HK
dc.identifier.issn0340-2061en_HK
dc.identifier.urihttp://hdl.handle.net/10722/67695-
dc.description.abstractIn male tammar wallabies, the scrotum is the first organ to become sexually differentiated, 4-5 days before birth (day 22 of gestation). This is followed by enlargement of the gubernaculum and processus vaginalis one day before birth. However the indifferent gonad does not show any signs of testicular cord formation or androgen production until later, at around the time of birth; this is more pronounced at 2 days post-partum (p.p.), when the testis takes on a characteristic rounded appearance. Primordial germ cells proliferate throughout the testis at this time, although the testis does not become significantly heavier than the ovary until around 80 days p.p.. In females, the appearance of the mammary glands is the first sign of sexual differentiation 4-5 days before birth. The indifferent gonad first shows signs of developing an ovarian cortex and medulla 7 days after birth. The migrating germ cells are confined to the cortex, and first start to enter meiosis about 25 days after birth. The Wolffian (mesonephric) ducts are patent to the urogenital sinus in fetuses at day 21 of gestation. In the female they have started to regress by 10 days p.p. and only rudiments remain by day 25 p.p.. The Mullerian (paramesonephric) ducts develop adjacent to the cranial pole of the mesonephros at about day 25 of gestation and grow caudally to meet the urogenital sinus between days 2 and 7 p.p.. The Mullerian duct of the female develops a prominent ostium abdominale by day 9 p.p., but this structure has completely regressed in males by day 13 p.p.. The testis and ovary both migrate caudally, together with the adjacent mesonephros, at about day 10 p.p.. The ovaries remain around the level of lumbar vertebra 4 after about day 7 p.p., while the testes continue to descend. The testes enter the internal inguinal ring at about day 25 p.p., about the time that prostatic buds first appear in the urogenital sinus, and are in the inguinal canal from days 25 to 36 p.p.. They enter the scrotum at around day 36 p.p., and testicular descent is complete by days 65-72 p.p.. Melanin develops in the tunica vaginalis 72 days after birth. The overall development of the urogenital system in this marsupial is similar to that of eutherians but the sequence of events differs, with some aspects of genital differentiation preceding gonadal differentiation, apparently because they are directly controlled by X-linked genes, rather than indirectly controlled by gonadal steroids.en_HK
dc.languageengen_HK
dc.publisherSpringer Verlag. The Journal's web site is located at http://link.springer.de/link/service/journals/00429/index.htmen_HK
dc.relation.ispartofAnatomy and Embryologyen_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshAnimals, Newbornen_HK
dc.subject.meshFemaleen_HK
dc.subject.meshGenitalia - anatomy & histology - embryology - growth & developmenten_HK
dc.subject.meshGerm Cells - growth & development - ultrastructureen_HK
dc.subject.meshGonads - anatomy & histology - growth & developmenten_HK
dc.subject.meshKidney - anatomy & histology - growth & developmenten_HK
dc.subject.meshMacropodidae - embryology - physiologyen_HK
dc.subject.meshMaleen_HK
dc.subject.meshMammary Glands, Animal - anatomy & histology - growth & developmenten_HK
dc.subject.meshMesonephros - anatomy & histology - growth & developmenten_HK
dc.subject.meshMicroscopy, Electron, Scanningen_HK
dc.subject.meshMullerian Ducts - anatomy & histology - growth & developmenten_HK
dc.subject.meshScrotum - anatomy & histology - growth & developmenten_HK
dc.subject.meshSex Characteristicsen_HK
dc.subject.meshSex Differentiationen_HK
dc.subject.meshTestis - anatomy & histology - growth & developmenten_HK
dc.subject.meshUreter - anatomy & histology - growth & developmenten_HK
dc.subject.meshUrinary Bladder - anatomy & histology - growth & developmenten_HK
dc.subject.meshWolffian Ducts - anatomy & histology - growth & developmenten_HK
dc.titleSexual differentiation of the urogenital system of the fetal and neonatal tammar wallaby, Macropus eugeniien_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0340-2061&volume=194&spage=111&epage=134&date=1996&atitle=Sexual+differentiation+of+the+urogenital+system+of+the+fetal+and+neonatal+tammar+wallaby,+Macropus+eugeniien_HK
dc.identifier.emailO, WS:owaisum@hkucc.hku.hken_HK
dc.identifier.authorityO, WS=rp00315en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.pmid8827321-
dc.identifier.scopuseid_2-s2.0-8944260902en_HK
dc.identifier.hkuros21017en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-8944260902&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume194en_HK
dc.identifier.issue2en_HK
dc.identifier.spage111en_HK
dc.identifier.epage134en_HK
dc.identifier.isiWOS:A1996UW92400001-
dc.publisher.placeGermanyen_HK
dc.identifier.scopusauthoridRenfree, MB=7005587252en_HK
dc.identifier.scopusauthoridO, WS=6701729369en_HK
dc.identifier.scopusauthoridShort, RV=7202190995en_HK
dc.identifier.scopusauthoridShaw, G=7401773619en_HK

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