The relation of sex hormones to pigmentation and to testis descent in the opossum and ground squirrel

Finkel, Miriam P.

doi:10.1002/aja.1000760105

Cited by 30 publications

(6 citation statements)

References 57 publications

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“…Gubernacular structures have been studied primarily as part of male genital development (review see van der Schoot 1996B), though development of the human female gubernaculum has been well-documented (Barteczko and Jacob 2000). In the female, the guber- (Burns 1939(Burns , 1945(Burns , 1961Finkel 1945) following a poorly understood process. The gubernaculum in the tammar wallaby, Macropus eugenii, develops as a cord of connective tissue, from the nephrogenic cord at the posterior end of the gonad and mesonephros; it connects with the anterior abdominal wall, is first identified on day 22 of embryonic life (E22) and no sex difference in its structure is apparent until E25, the day before birth (Renfree et al 1996).…”

Section: Discussionmentioning

confidence: 41%

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

Mackay

Xie

Ullmann

et al. 2004

Anatomy and Embryology

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Postnatal phenotypic sex differentiation has been investigated in a laboratory marsupial, Monodelphis domestica, as part of a larger study to resolve apparent discrepancies between eutherian and marsupial mammals. These include the formation of sex-specific structures in marsupials prior to gonadal differentiation and the retention in both sexes of structures which are sex-specific in eutherians. The time-course and nature of differentiation was investigated in 131 specimens ranging in age from the day of birth to 56 days. Patent wolffian ducts extend to the urogenital sinus in both sexes at birth, while müllerian ducts are identified on day 1 and grow in a cranio-caudal direction to reach the urogenital sinus on day 6. The male müllerian duct shows signs of regression at its cranial end on day 10 and throughout its length on day 12; its lumen has completely disappeared by day 15. By this time the epididymis and vas deferens have developed from the wolffian duct; their histological differentiation occurs between days 26 and 56. Prostatic buds are identifiable in tissue surrounding the male urethra on day 14. In the female, the wolffian duct is larger than the müllerian duct until day 14; thereafter the wolffian duct begins to regress at its cranial end, disappearing by day 17, whereas the müllerian duct begins to enlarge, converging with its fellow at the urogenital sinus by day 19. Lateral vaginae, vaginal culs-de-sac, uteri and oviducts have differentiated from the müllerian ducts by day 25. Gonads of both sexes are elongated in shape at birth, attached along the medial aspect of the large mesonephroi in the abdominal cavity. However, from day 3 onwards the testis becomes more rounded than the ovary. Degeneration of the male mesonephros begins about day 10 and is almost completed by day 19; the female mesonephros is still relatively large at day 14 though it too has almost disappeared by day 19. By postnatal day 13 the abdominal phase of testis descent is underway and the inguinal phase begins at day 15. Testes have reached the scrotal sac by day 24 and achieve their final position at the base of the scrotum by day 28. In summary, postnatal reproductive tract development and gonadal descent has been examined in this important biomedical model, where differentiation of the wolffian and müllerian ducts takes place after gonadal differentiation, according to the normal eutherian pattern.

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Section: Discussionmentioning

confidence: 41%

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

Mackay

Xie

Ullmann

et al. 2004

Anatomy and Embryology

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“…microtarsus scrotum shows the lining tunics, namely, dartos tunic which is closely related to the skin and allows the withdrawal of the scrotum; vaginal tunic at the parietal and visceral section; albuginea tunica adherent to the testicles, as described in Philander opossum NOGUEIRA, 1990b). Whereas the parietal vaginal tunic was highly pigmented with melanin as in American marsupials (FINKEL, 1945), the visceral tunic had a light hue and was similar to that in Didelphis sp. (BARROS et al, 2003).…”

Section: Discussionmentioning

confidence: 43%

Morphological study of the male genital organs of Gracilinanus microtarsus

Lima

Santos

Viana

et al. 2013

Braz. J. Vet. Res. Anim. Sci.

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Gracilinanus microtarsus is one of the smallest marsupials on earth. Since it spreads seeds, it has great ecological relevance. However, its reproduction data, especially those related to the anatomy of its reproduction apparatus, are scarce in the literature. Current analysis describes the male genital organs of six adult specimens of G. microtarsus. Macroscopic studies were undertaken on dissected organs, whereas histological studies were performed by inclusion technique in paraffin and by hematoxylin and eosin, and Masson trichrome staining. The male genital organs and accessory glands of G. microtarsus consist of two testicles within a pendular scrotum, placed cranially to the penis, featuring a histology consisting of seminiferous tubules with spermatogenic cells, spermatozoa and Sertoli cells, and a peritubular region with Leydig cells; testicles closely associated with epididymis with head, body and tail, with histological differences between the different regions; deferent ducts; funiculus spermaticus; accessory glands composed of prostate, divided into three distinct segments and bulbourethral glands; pelvic and penile urethra and penis with bifid glans. Results show that the male genital organs and accessory glands of G. Microtarsus are anatomically similar to that found in Didelphis sp. and other marsupials groups, with slight details such as the site of each organ.Keywords: Didelphimorphia. Marsupials. Reproduction. Prostatic segments. ResumoGracilinanus microtarsus é um dos menores marsupiais do mundo. Possui grande potencial dispersor de sementes e por esta razão apresenta grande importância ecológica. No entanto, dados em relação à reprodução desses animais são escassos na literatura, principalmente, aqueles relacionados à anatomia dos órgãos do aparelho reprodutor. Por essa razão, objetivamos com este estudo realizar uma descrição dos órgãos genitais masculinos em seis exemplares de G. microtarsus adultos. Para tanto, realizamos estudos macroscópicos por dissecação dos órgãos e estudos histológicos por técnica de inclusão em parafina e coloração em hematoxilina e eosina, e tricromo de Masson. Encontramos, que os órgãos genitais masculinos e glândulas acessórias em G. microtarsus são representados por dois testículos localizados dentro de um escroto pendular, posicionados cranialmente ao pênis, cuja histologia revelou túbulos seminíferos com espermatogônias, espermatozoides e células de Sertoli e região peritubular com células de Leydig; testículos em íntima associação com os epidídimos, divididos em cabeça, corpo e cauda, com diferenças histológicas entre as diferentes regiões; ductos deferentes; funículo espermático; glândulas anexas compostas pelas glândulas prostáticas divididas em três distintos segmentos e glândulas bulbouretrais; uretra pélvica e peniana e um pênis com glande bífida. Concluímos que os órgãos genitais e as glândulas acessórias masculina de G. microtarsus, anatomicamente são muito semelhantes aos dos Didelphis sp. e outros grupos de marsupiais, diferenciando-se apenas...

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“…Pigmentation of scrotal skin is under testicular control and depends on testosterone secretion (Finkel 1945). Scrotal pigmentation increased during the first 4 weeks post heterothermy and remained visible until the end of the study.…”

Section: Experimental Males (N = 4)supporting

confidence: 38%

Testis development and testosterone secretion in captive European ground squirrels before, during, and after hibernation

Strauss

Hoffmann

Vielgrader³

et al. 2008

Acta Theriol

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Timing of reproduction constitutes a major decision in life history delimited by resource availability and mortality risk. Hibernating species are subject to additional temporal constraints. Both sexes have to cope with a short active season in completing gonadal development, reproduction, and prehibernatory fattening. Males have to adapt to the strict seasonality and must be reproductively competent [47] Acta Theriologica 53 (1): 47-56, 2008. . 2008. Testis development and testosterone secretion in captive European ground squirrels before, during, and after hibernation. Acta Theriologica 53: 47-56.In some hibernating species, an extended euthermic period before spring emergence has been reported during which testicular maturation occurred. In this study, we investigated whether male European ground squirrels Spermophilus citellus (Linnaeus, 1766) develop scrotal testes before or after the termination of hibernation. The course of testis development and testosterone concentrations were examined in young-of-year male ground squirrels (n = 4) before, during, and after their first hibernation. In the environmental chamber, all animals showed regular hibernation patterns with decreasing torpor bout lengths prior to the end of hibernation. Four weeks before hibernation ended, testosterone levels were elevated during spontaneous arousals. Testosterone concentrations peaked during the first 2 months post heterothermy and decreased thereafter. In 2 experimental males, testes descended from the inguinal region into the scrotum shortly before the end of heterothermy. The state of testis development and testosterone secretion corresponded to that found in semi-free-living males at spring emergence. Testis size increased in active animals to maximum widths during weeks 3 and 4 post heterothermy. Scrotal skin pigmentation was absent until heterothermy ended and developed during the first month thereafter. The data suggest that male S. citellus do not need a pre-emergence euthermic period for reproductive development.

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The relation of sex hormones to pigmentation and to testis descent in the opossum and ground squirrel

Cited by 30 publications

References 57 publications

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

Postnatal development of the reproductive system in the grey short-tailed opossum, Monodelphis domestica

Morphological study of the male genital organs of Gracilinanus microtarsus

Testis development and testosterone secretion in captive European ground squirrels before, during, and after hibernation

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