Cytological Differentiation of Fetal Bovine Gonads

Rajakoski, E.; Hafez, E. S. E.

doi:10.1159/000129810

Cited by 8 publications

(3 citation statements)

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“…We found that in bovine embryos, testis cords form between CRL 25 and 27 (around CS 17) in agreement with previous studies [Rajakoski and Hafez, 1964;Jost et al, 1972;Dominguez et al, 1988], shortly after the activation of SRY expression at CRL 20 (CS 16) ( fig. 6 ).…”

Section: Testis Cord Formationsupporting

confidence: 93%

Profiles of Gonadal Gene Expression in the Developing Bovine Embryo

Ross

Bowles²,

Hope³

et al. 2009

Sex Dev

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Our current understanding of the molecular basis of sex determination and gonadal development in humans is mostly an extrapolation of knowledge gained from studies in the mouse. However, the timing of gene expression in the mouse is unusual among mammals, and it is therefore important that data from other models are also available to help elucidate this pivotal process in human development. Here we describe the sequence of molecular and morphological events marking testis differentiation in bovine embryos. The genital ridges first appeared at CRL 12 (day 32). SRY expression began at CRL 18 (day 37) and peaked at CRL 20 (day 39), leading to a cascade of regulatory, signaling, and steroidogenic gene expression at later stages, detected by quantitative real-time RT-PCR and immunohistochemistry. Testis cords were distinguishable at CRL 27 (day 42). We conclude that the timing of gene expression observed in developing human embryos is much more similar to bovine development than it is to the mouse. Therefore, Bos taurus may represent a useful model in which to study gene expression during sex determination, relevant to human development.

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Section: Testis Cord Formationsupporting

confidence: 93%

Profiles of Gonadal Gene Expression in the Developing Bovine Embryo

Ross

Bowles²,

Hope³

et al. 2009

Sex Dev

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“…As far as we are aware, no seminiferous tubules have been reported in the literature in freemartins under 20 cm crown-rump length. They were absent in freemartins of the following sizes: 3-2 cm (Bissonnette, 1928a); 3-75 cm (Lillie, 1923); 6-75 to 7-5 cm (three cases), 9 cm (two cases), 11-75 cm, 12-5 cm, 16-3 cm and 17 cm (Chapin, 1917;Bissonnette, 1924Bissonnette, , 1928b and on Day 60 (Rajakoski & Hafez, 1964). On the contrary, seminifer¬ ous tubules were inconstantly found in 20to 28-cm freemartins.…”

Section: The Early Freemartin Effectmentioning

confidence: 95%

Freemartins in Cattle: The First Steps of Sexual Organogenesis

Jost¹,

Vigier²,

Prépin³

1972

Reproduction

138

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Multiple pregnancies were obtained in cows treated with gonadotrophic hormones and the fetuses were removed 39 to 62 days after mating. This covers the period of sexual organogenesis in males from the initial differentiation of the testes to the final establishment of most male structures. Twenty-nine pregnancies resulting in heterosexual fetuses with fused chorions and vascular anastomoses provided forty-eight presumptive freemartins. The genital tract was studied histologically and gonadal size was determined by the paper weight method. No difference was observed between control females and presumptive freemartins up to 48 days. Thereafter, growth of the presumptive ovaries practically stopped in freemartins and the diameter of the upper part of their M\l=u"\llerian ducts decreased, as in males. Contrary to older views, the first freemartin effects occurred at the same stage (49 to 52 days) in all the presumptive freemartins. Ovarian and M\l=u"\llerianinhibition begins simultaneously and a significant correlation between the degree of inhibition of both structures was obtained. The penis, scrotum and prostate were absent in all freemartins until Day 60. In only one case was the ano-genital distance slightly increased. A delayed appearance of seminal vesicles was found in three out of seven freemartins at 61 and 62 days. There was a notable absence of seminiferous tubules in the gonads of all these freemartins. It is suggested that if these tubules are present after birth it is because they have developed later. The factors responsible for the freemartin effect still remain to be discovered. Ovarian and M\l=u"\llerianinhibitions occur during the period of time when the external genitalia of males become masculinized. This suggests that a factor of male origin which inhibits both the ovaries and the M\l=u"\llerianducts and which is distinct from the masculinizing hormone could be involved. Other possibilities are also discussed. Males Females 39 to 40 42 to 43 45 47 48 to 49

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“…Freemartins arise as a consequence of chorionic fusion and further vascular anastomosis [reviewed in Jost et al, 1972], which allows for the exchange of blood between the 2 embryos and results in a masculinising effect in the female co-twin. Although the external genitalia are typically female, freemartins have several internal intersex features, including defective development of the Müllerian ducts, which implies either aplasia or hypoplasia of the uterus [Laster et al, 1971], and reduced vaginal length [Rajakoski and Hafez, 1964], accompanied by the formation of male accessory sex glands (i.e. vesicular glands, prostate and vas deferens) [Sattar, 1977] and testis-like structures in the gonad [Goss, 1950; for a detailed description of the freemartin phenotype, see Khan and Foley, 1994].…”

Section: Freemartinism In Bovids and Pigsmentioning

confidence: 99%

Natural Exceptions to Normal Gonad Development in Mammals

Jiménez

Barrionuevo²,

Burgos³

2012

Sex Dev

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Gonads are the only organs with 2 possible developmental pathways, testis or ovary. A consequence of this unique feature is that mutations in genes controlling gonad development give rise not only to gonadal malformation or dysfunction but also to frequent cases of sex reversal, including XY females, XX males and intersexes. Most of our current knowledge on mammalian sex determination, the genetic process by which the gonadal primordia are committed to differentiate as either testes or ovaries, has derived mainly from the study of sex-reversed mice obtained by direct genetic manipulation. However, there are also numerous cases of natural exceptions to normal gonad development which have been described in a variety of mammals, including both domestic and wild species. Here, we review the most relevant cases of: (1) natural, non-induced sex reversal and intersexuality described in laboratory rodents, including Sxr and B6-Y^DOM mice; (2) sex reversal in domestic animals, including freemartinism in bovids and pigs, XX sex reversal in pigs, goats and dogs, XY sex reversal in the horse, and sex chromosome chimerism and sex reversal in the cat, and (3) sex reversal in wild mammals, including the generalised true hermaphroditism described in talpid moles, XY sex reversal in Akodon, Microtus and Dicrostonyx species, males lacking a Y chromosome and SRY in Ellobius lutescens, the X* chromosome of Myopus schisticolor, and sex chromosome mosaicism and X0 females in Microtus oregoni. These studies are necessary to elucidate particular aspects of mammalian gonad development in some instances and to understand how the genetic mechanisms controlling gonad development have evolved.

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Cytological Differentiation of Fetal Bovine Gonads

Cited by 8 publications

References 0 publications

Profiles of Gonadal Gene Expression in the Developing Bovine Embryo

Profiles of Gonadal Gene Expression in the Developing Bovine Embryo

Freemartins in Cattle: The First Steps of Sexual Organogenesis

Natural Exceptions to Normal Gonad Development in Mammals

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