Urogenital system of the spotted hyena (Crocuta crocuta Erxleben): A functional histological study

@article{Cunha2003UrogenitalSO,
  title={Urogenital system of the spotted hyena (Crocuta crocuta Erxleben): A functional histological study},
  author={G. Cunha and Yuzhuo Wang and N. Place and Wenhui Liu and L. Baskin and S. Glickman},
  journal={Journal of Morphology},
  year={2003},
  volume={256}
}
The unique urogenital anatomy and histology of female spotted hyenas (Crocuta crocuta Erxleben) was reexamined to identify adaptations of "structure" that enable/facilitate urination, mating, and parturition through the clitoris. [...] Key Result Adaptive features of the upper genital tract were a helical-shaped uterine cavity, extensive smooth muscle in the uterus and vagina, and a newly discovered submucosal mucous urogenital gland (SMUG) located immediately caudal to the vagina.Expand
Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta).
TLDR
Data is summarized on development of the external genitalia of the spotted hyena to indicate that early formation of the phallus in both males and females is independent of androgens, and that estrogens play a critical role in penile and clitoral development. Expand
The Ontogeny of the Urogenital System of the Spotted Hyena (Crocuta crocuta Erxleben)1
TLDR
It is concluded that gross masculinization of phallic size and shape of male and female fetuses is androgen-independent, but that sexual dimorphism of internal phallic structure is dependent on fetal testicular androgens acting via AR in the relevant cells/tissues. Expand
Spotted hyaenas and the sexual spectrum: reproductive endocrinology and development.
TLDR
Insight into the costs and benefits of androgen exposure on spotted hyaena reproductive development, endocrinology and behaviour emphasizes the delicate balance that sustains reproductive success, forces a re-evaluation of how the authors define masculine versus feminine sexual characteristics, and motivates reflection about the representative value of model species. Expand
A neuroanatomical comparison of humans and spotted hyena, a natural animal model for common urogenital sinus: clinical reflections on feminizing genitoplasty.
TLDR
The neuroanatomical characteristics of the spotted hyena may be a useful model to simulate the anatomy of common urogenital sinus anomaly in humans and the pattern of clitoral innervation for the unique challenges faced by female spotted hyenas is examined. Expand
Development of the Penile Urethra in the Tammar Wallaby
TLDR
It is shown that penile development and critical changes in the positioning of the urethra occur in the male phallus begin during an early window of time when androgens are high, suggesting that there is an earlywindow of time before day 60 when androgen imprinting must occur for normal peniledevelopment and closure of theUrethral groove. Expand
Variation in Penile and Clitoral Morphology in Four Species of Moles
TLDR
This dissertation is focused on four species of moles, all of which defy the conventionally obvious visual distinctions between males and females, and the potential role of hormones in development of the external genitalia in these species is investigated. Expand
Endocrine differentiation of fetal ovaries and testes of the spotted hyena (Crocuta crocuta): timing of androgen-independent versus androgen-driven genital development.
TLDR
The hypothesis that external genital morphology is probably androgen-independent initially, but that fetal testicular androgens modify the secondary, male-specific phallic form and accessory organs is supported. Expand
Variation in Female Reproductive Tract Morphology of the Common Bottlenose Dolphin (Tursiops truncatus)
TLDR
A standardized measurement protocol is developed for the reproductive tracts of female cetaceans to assess variation in morphometrics within the common bottlenose dolphin (Tursiops truncatus), and determine if vaginal muscle is skeletal, and therefore of somatic origin in this species. Expand
External genital morphology of the ring‐tailed lemur (Lemur catta): Females are naturally “masculinized”
TLDR
Those of the female ring‐tailed lemur are characterized as moderately “masculinized,” highlighting certain morphological similarities and differences between ring‐tails lemurs and the most male‐like of female mammals, the spotted hyena, and calling attention to a potential hormonal mechanism of “Masculinization” in female lemur development. Expand
Mammalian sexual differentiation: lessons from the spotted hyena
TLDR
Effects on aggression and dominance might offset the reproductive 'costs' of female androgenization in utero, and reduce reproductive success in adult female spotted hyenas. Expand
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TLDR
The hyena is unique among Carnivora in the possession of a hemochorial villous placenta, allied structurally more to that of New World monkeys than to the other carnivores. Expand
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TLDR
Investigating the timing of urogenital development and placental production of androgen during early and mid-gestation concluded that androgen is produced by the placenta and secreted into the fetal circulation from early in pregnancy when masculinization is first evident, before differentiation of the fetal ovary. Expand
Pattern and source of secretion of relaxin in the reproductive cycle of the spotted hyena (Crocuta crocuta).
TLDR
It is concluded that relaxin secretion coincides with changes in extensibility of clitoral connective tissues 1) during growth of the clitoris in juveniles and 2) near the time of parturition in adults. Expand
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The weight of the skinned phallus and the diameter of its shaft and glans did not differ significantly in the two sexes of spotted hyaena, but phallus length was greater in males. The urethra of theExpand
Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 3. Effects of juvenile gonadectomy.
TLDR
It is suggested that postnatal phallic growth is largely independent of gonadal steroids, with oestrogenic facilitation of female-typical clitoral characteristics in spotted hyaenas. Expand
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TLDR
Since testosterone inhibits formation of the lower vagina, the timing of exposure to systemic testosterone in congenital adrenal hyperplasia will determine the phenotypic appearance of the external genitalia and effect of testosterone on the development of theLower genital tract. Expand
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TLDR
Pregnant spotted hyaenas were treated with anti-androgens to interfere with the unusually masculine 'phallic' development that characterizes females of this species, and the present data suggest that development of the male penis and scrotum and the female clitoris and pseudoscrotum, in spotted hyAenas may involve both androgen-dependent and androgen -independent components. Expand
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TLDR
Onufs nucleus was examined in adult and neonatal spotted hyenas and was found to be sexually dimorphic in the typical mammalian pattern, and the morphology of the bulbocavernosus muscle was feminized in males exposed to anti‐androgen in utero. Expand
Reproduction in the Spotted Hyaena, Crocuta crocuta (Erxleben)
From time immemorial it has been known that there is something peculiar about the sexual anatomy and physiology of the spotted hyaena. The writers of antiquity relate the legend that this animal isExpand
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TLDR
Uterine/vaginal heterotypic tissue recombinations demonstrated that functional differentiation of uterine and vaginal epithelia required organ-specific stromal factors, and stroma signals regulating epithelial proliferation appeared to be nonspecific in the uterus and vagina. Expand
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