RESUMO
Hemigrammus xaveriellus sp. nov. is described from the upper Río Vaupés basin (Amazon basin), Departamento Guaviare, Colombia. It is distinguished from all congeners by the combination of the following characters: presence of a conspicuous, dark, longitudinal midlateral stripe extending along the body; presence of a conspicuous rounded, horizontally elongated humeral blotch anterior to the beginning of the dark midlateral stripe; seven scale rows between the dorsal fin and lateral line (vs. five to six); and five scale rows between the lateral line and pelvic-fin insertion (vs. three to four). The single mature male of He. xaveriellus possessed a well-developed urogenital papilla, an unusual feature among characids. The presence of an enlarged urogenital papilla in the family is discussed, and comments regarding the putative relationships of the new species are presented.
Assuntos
Characidae/anatomia & histologia , Characidae/classificação , Sistema Urogenital/anatomia & histologia , Animais , Brasil , Colômbia , Masculino , Rios , Especificidade da EspécieRESUMO
The success of fishes in different environments is related with the variation of reproductive strategies developed by the systematic group, which is reflected in the morphology of the reproductive system and can have ecological and evolutionary implications. This study comparatively analyzed the morphological characteristics of the male and female reproductive systems of ostariophysan fish species from the upper Das Velhas River in the São Francisco River basin, Brazil. In order to accomplish this, 393 specimens belonging to seven fish species were sampled between April 2010 and June 2015 for histological, ultrastructural, histochemical, and morphometric analyses. All the species examined have anastomosing tubular testes with unrestricted distribution of spermatogonia. Astyanax bimaculatus, A. fasciatus, A. scabripinnis, and Harttia torrenticola had their spermatozoa embedded in a glycoprotein secretion within the tubule lumen. Most species had type I spermiogenesis, whereas Rhamdia quelen had type III spermiogenesis. While all females examined had asynchronous oocyte development, there were remarkable morphological, histochemical, and morphometric differences in the ovarian follicles and enveloping layers. Hoplias malabaricus and H. torrenticola, which exhibit parental care behaviour, had a significantly larger diameter of vitellogenic oocytes and larger spermatozoa nuclei. Apareiodon ibitiensis, H. torrenticola, and A. scabripinnis, species that have rheophilic preferences, exhibited a thicker zona radiata than the other species examined. The follicular cells of R. quelen and H. torrenticola were columnar and produced a jelly coat and mucosubstances, respectively. The females of the seven fish species studied show a correlation of the reproductive strategies with the reproductive system morphology, while males retained more similar morphological characteristics between species. J. Morphol. 278:170-181, 2017. © 2016 Wiley Periodicals,Inc.
Assuntos
Peixes/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Animais , Brasil , Feminino , Masculino , RiosRESUMO
Time of exposure and light intensity rearing house may affect the performance and egg quality of laying quails. This research aimed at evaluating the live performance, egg quality, biometry of the reproductive system, and the gastrointestinal tract of Japanese quails (Coturnix coturnix japonica) exposed to artificial light-emitting diodes (LED) of different colors in comparison with fluorescent lamps. A total of 240 Japanese quails were distributed in completely randomized experimental design with four treatments (fluorescent lamp, and green, red, or blue LED lamps) with six replicates of 10 birds each. Average egg weight and eggshell thickness were different (p < 0.05) when LED bulbs were compared with fluorescent lamps. The egg weight of the birds exposed to the red LED was similar to those under a fluorescent lamp (p>0.05). The oviduct of 64-d-old hens exposed to green LED lighting was shorter (p < 0.05) than those exposed to the fluorescent lamp. Red LED can be used to replace the fluorescent lamps, as they promote the same live performance, egg quality, and morphological development of the reproductive tract of laying Japanese quails.(AU)
Assuntos
Animais , Iluminação/instrumentação , Coturnix/fisiologia , Coturnix/crescimento & desenvolvimento , Ovos/análise , Sistema Urogenital/anatomia & histologia , Trato Gastrointestinal/anatomia & histologia , Casca de Ovo , Produtos Avícolas/análiseRESUMO
Time of exposure and light intensity rearing house may affect the performance and egg quality of laying quails. This research aimed at evaluating the live performance, egg quality, biometry of the reproductive system, and the gastrointestinal tract of Japanese quails (Coturnix coturnix japonica) exposed to artificial light-emitting diodes (LED) of different colors in comparison with fluorescent lamps. A total of 240 Japanese quails were distributed in completely randomized experimental design with four treatments (fluorescent lamp, and green, red, or blue LED lamps) with six replicates of 10 birds each. Average egg weight and eggshell thickness were different (p 0.05). The oviduct of 64-d-old hens exposed to green LED lighting was shorter (p < 0.05) than those exposed to the fluorescent lamp. Red LED can be used to replace the fluorescent lamps, as they promote the same live performance, egg quality, and morphological development of the reproductive tract of laying Japanese quails.
Assuntos
Animais , Coturnix/crescimento & desenvolvimento , Coturnix/fisiologia , Iluminação/instrumentação , Ovos/análise , Casca de Ovo , Produtos Avícolas/análise , Sistema Urogenital/anatomia & histologia , Trato Gastrointestinal/anatomia & histologiaRESUMO
Omalonyx geayi Tillier, 1980 was originally described on the basis of specimens from Kaw swamp, French Guiana. This species distinguished from other of Omalonyx d'Orbigny, 1837: (i) by hermaphrodite duct twice as long and sacculate, without radial ducts but a funnel-shaped insertion on the ovariotestis, and (ii) by longitudinal wrinkled folds on the phallus inner wall. Two recent collections - from Trinidad and Carauari (Amazonas, Brazil) included specimens with ovariotestis and hermaphrodite duct morphologies similar to that originally described for O. geayi, but with phallus morphology not consistent with identification as O. geayi. A further eight lots, from Suriname, Ecuador, Brazil (Amazonas and Alagoas States), Bolivia and Cayenne-Kourou Road in French Guiana comprised specimens with phallus morphology analogous to O. geayi and ovariotestis and hermaphrodite duct similar to that of other Omalonyx species. Based on histological examination, and earlier phylogenetic analyses of morphological characters, we conclude that the ovariotestis and hermaphrodite duct conditions previously described for O. geayi were based on parasitized specimens. Accordingly, O. geayi is redescribed, and new information presented on the species' wide distribution in South America.(AU)
Omalonyx geayi Tillier, 1980 foi originalmente descrita com base em exemplares procedentes do pântano Kaw na Guiana Francesa. A espécie se diferencia das demais de Omalonyx d'Orbigny, 1837: (i) pelo ducto hermafrodita duas vezes mais longo e convoluto, cuja inserção no ovariotestis é em formato de um funil, ao invés de ductos radiais, e (ii) pelas pregas longitudinais enrugadas na parede interna do falo. Dois lotes - procedentes de Trinidad e Carauari (Amazonas, Brasil) - apresentaram espécimes com ovariotestis e ducto hermafrodita similares aos da descrição original de O. geayi, porém com a morfologia do falo distinta. Outros oito lotes procedentes do Suriname, Equador, Brasil (estados do Amazonas e Alagoas), Bolívia e estrada Cayenne-Kourou na Guiana Francesa continham exemplares com morfologia do falo análoga à de O. geayi, todavia com ovariotestis e ducto hermafrodita similares aos das demais espécies de Omalonyx. Conforme resultados do estudo histológico e da análise filogenética com caracteres morfológicos, concluímos que as condições mencionadas para o ovariotestis e ducto hermafrodita na descrição de O. geayi foi baseada em espécimes parasitados. Omalonyx geayi é redescrita e novas informações sobre a distribuição na América do Sul são apresentadas.(AU)
Assuntos
Animais , Gastrópodes/classificação , Gastrópodes/anatomia & histologia , Sistema Urogenital/anatomia & histologiaRESUMO
Omalonyx geayi Tillier, 1980 was originally described on the basis of specimens from Kaw swamp, French Guiana. This species distinguished from other of Omalonyx d'Orbigny, 1837: (i) by hermaphrodite duct twice as long and sacculate, without radial ducts but a funnel-shaped insertion on the ovariotestis, and (ii) by longitudinal wrinkled folds on the phallus inner wall. Two recent collections - from Trinidad and Carauari (Amazonas, Brazil) included specimens with ovariotestis and hermaphrodite duct morphologies similar to that originally described for O. geayi, but with phallus morphology not consistent with identification as O. geayi. A further eight lots, from Suriname, Ecuador, Brazil (Amazonas and Alagoas States), Bolivia and Cayenne-Kourou Road in French Guiana comprised specimens with phallus morphology analogous to O. geayi and ovariotestis and hermaphrodite duct similar to that of other Omalonyx species. Based on histological examination, and earlier phylogenetic analyses of morphological characters, we conclude that the ovariotestis and hermaphrodite duct conditions previously described for O. geayi were based on parasitized specimens. Accordingly, O. geayi is redescribed, and new information presented on the species' wide distribution in South America.
Omalonyx geayi Tillier, 1980 foi originalmente descrita com base em exemplares procedentes do pântano Kaw na Guiana Francesa. A espécie se diferencia das demais de Omalonyx d'Orbigny, 1837: (i) pelo ducto hermafrodita duas vezes mais longo e convoluto, cuja inserção no ovariotestis é em formato de um funil, ao invés de ductos radiais, e (ii) pelas pregas longitudinais enrugadas na parede interna do falo. Dois lotes - procedentes de Trinidad e Carauari (Amazonas, Brasil) - apresentaram espécimes com ovariotestis e ducto hermafrodita similares aos da descrição original de O. geayi, porém com a morfologia do falo distinta. Outros oito lotes procedentes do Suriname, Equador, Brasil (estados do Amazonas e Alagoas), Bolívia e estrada Cayenne-Kourou na Guiana Francesa continham exemplares com morfologia do falo análoga à de O. geayi, todavia com ovariotestis e ducto hermafrodita similares aos das demais espécies de Omalonyx. Conforme resultados do estudo histológico e da análise filogenética com caracteres morfológicos, concluímos que as condições mencionadas para o ovariotestis e ducto hermafrodita na descrição de O. geayi foi baseada em espécimes parasitados. Omalonyx geayi é redescrita e novas informações sobre a distribuição na América do Sul são apresentadas.
Assuntos
Animais , Gastrópodes/anatomia & histologia , Gastrópodes/classificação , Sistema Urogenital/anatomia & histologiaRESUMO
PURPOSE: To analyze Pten and Smad4 gene expression in the urogenital system of Wistar rats in differents ages. METHODS: Pten and Smad4 mRNA expression was assessed in the bladder, ventral prostate, testis, ovaries, and uterus by real-time PCR. Statistical analysis using the ANOVA (p<0.05). RESULTS: Pten levels showed a progressive age-dependent increase in the bladder (male and female) and prostate and were elevated in the ovaries of the middle-aged. In the uterus, no statistically significant differences were observed; in the testis, increased and decreased levels were seen in young adult and middle-aged rats, respectively. Smad4 expression was downregulated in the ovaries of the pubertal group but increased in the middle age group. In the uterus, Smad4 expression in the oldest group was higher than the others groups. In the testis, Smad4 expression steadily declined with age; in the prostate, it was higher in middle-aged rats than in younger rats. A similar trend was observed in the bladder of male and female middle-aged rats, compared with the pubertal group. CONCLUSION: The changes in phosphatase tensin homologue and Smad4 mRNA expression in Wistar rats appear to be associated with hormonal modifications in puberty and may be related to early follicular and testicular development. .(AU)
Assuntos
Animais , Ratos , Fatores Etários , Genes/genética , Sistema Urogenital/anatomia & histologia , Puberdade/metabolismo , Testículo/anatomia & histologia , Ratos/classificaçãoRESUMO
Avaliou-se o efeito da suplementação com geleia real sobre a morfometria do aparelho genital, resposta superovulatória e qualidade embrionária de coelhas. Trinta e seis fêmeas foram distribuídas em quatro grupos (G), sendo: G1 (n=9) formado por animais não suplementados com geleia real, e G2, G3 e G4 (n=9 em cada grupo) por animais suplementados com 10, 20 e 40mg/dia de geleia real. A superovulação consistiu na aplicação de 40UI de gonadotrofina coriônica equina, seguida por 40UI de gonadotrofina coriônica humana, via intramuscular, 48 horas após, e submetidas à cobrição natural. Os animais foram sacrificados, e os embriões coletados 72 horas após a cópula. Não houve diferença estatística entre tratamentos para as variáveis analisadas. O peso médio do aparelho genital foi de 10,88±0,38g; dos ovários - direito e esquerdo -, 0,28±0,02g; e o índice gonadossomático, 0,02±0,0g. O número médio de estruturas totais recuperadas foi de 9,2±1,4; de embriões viáveis, 8,7±1,4; e de degenerados, 0,5±0,2. Dos embriões viáveis, 5,6±0,8 foram classificados como grau I; 2,3±0,5, como grau II; e 0,8±0,2, como grau III. A suplementação com geleia real na dose de até 40mg/dia não apresentou efeito estimulador sobre o aparelho genital e a qualidade embrionária de coelhas.(AU)
The purpose of this paper was to assess the effect of supplementation of royal jelly on the morphometry of the genital tract, superovulatory response and embryonic quality in adult rabbits. 36 rabbits were distributed in four groups (G), as follows: G1 (n=9): no supplementation with royal jelly, G2, 3 and 4 (n=9): supplementation with 10, 20 and 40mg/day of royal jelly. The superovulatory protocol consisted in the application of a dose of 40UI of Equine Chorionic Gonadotrophin, followed by a dose of UI of Human Chorionic Gonadotrophin, intramuscularly, 48 hours later, and submitted to natural cover. The animals were euthanasiated and the embryos collected 72 hours after copulation. There was no statistical difference for the analyzed variables (P>0.05). The average weight for the female genital tract was 10.89±0.38g; the average weight of right and left ovaries was 0.28±0.02g and the average gonadosomatic index rate was 0.02±0.0g. The number of total recovered structures was 9.2±1.4. The average number of viable embryos was 8.7±1.4 and of degenerated embryos was 0.5±0.2. Viable embryos were morphologically classified as degree I: 5.6±0.8; degree II: 2.3±0.5; degree III: 0.8±0.2. Royal jelly did not present stimulatory effect on organs related to the reproduction of rabbits, nor was it effective to improve their embryonic quality at dosages of up to 40mg of in natura royal jelly.(AU)
Assuntos
Animais , Sistema Urogenital/anatomia & histologia , Superovulação , Abelhas/metabolismo , Coelhos/classificaçãoRESUMO
Avaliou-se o efeito da suplementação com geleia real sobre a morfometria do aparelho genital, resposta superovulatória e qualidade embrionária de coelhas. Trinta e seis fêmeas foram distribuídas em quatro grupos (G), sendo: G1 (n=9) formado por animais não suplementados com geleia real, e G2, G3 e G4 (n=9 em cada grupo) por animais suplementados com 10, 20 e 40mg/dia de geleia real. A superovulação consistiu na aplicação de 40UI de gonadotrofina coriônica equina, seguida por 40UI de gonadotrofina coriônica humana, via intramuscular, 48 horas após, e submetidas à cobrição natural. Os animais foram sacrificados, e os embriões coletados 72 horas após a cópula. Não houve diferença estatística entre tratamentos para as variáveis analisadas. O peso médio do aparelho genital foi de 10,88±0,38g; dos ovários - direito e esquerdo -, 0,28±0,02g; e o índice gonadossomático, 0,02±0,0g. O número médio de estruturas totais recuperadas foi de 9,2±1,4; de embriões viáveis, 8,7±1,4; e de degenerados, 0,5±0,2. Dos embriões viáveis, 5,6±0,8 foram classificados como grau I; 2,3±0,5, como grau II; e 0,8±0,2, como grau III. A suplementação com geleia real na dose de até 40mg/dia não apresentou efeito estimulador sobre o aparelho genital e a qualidade embrionária de coelhas.
The purpose of this paper was to assess the effect of supplementation of royal jelly on the morphometry of the genital tract, superovulatory response and embryonic quality in adult rabbits. 36 rabbits were distributed in four groups (G), as follows: G1 (n=9): no supplementation with royal jelly, G2, 3 and 4 (n=9): supplementation with 10, 20 and 40mg/day of royal jelly. The superovulatory protocol consisted in the application of a dose of 40UI of Equine Chorionic Gonadotrophin, followed by a dose of UI of Human Chorionic Gonadotrophin, intramuscularly, 48 hours later, and submitted to natural cover. The animals were euthanasiated and the embryos collected 72 hours after copulation. There was no statistical difference for the analyzed variables (P>0.05). The average weight for the female genital tract was 10.89±0.38g; the average weight of right and left ovaries was 0.28±0.02g and the average gonadosomatic index rate was 0.02±0.0g. The number of total recovered structures was 9.2±1.4. The average number of viable embryos was 8.7±1.4 and of degenerated embryos was 0.5±0.2. Viable embryos were morphologically classified as degree I: 5.6±0.8; degree II: 2.3±0.5; degree III: 0.8±0.2. Royal jelly did not present stimulatory effect on organs related to the reproduction of rabbits, nor was it effective to improve their embryonic quality at dosages of up to 40mg of in natura royal jelly.
Assuntos
Animais , Abelhas/metabolismo , Superovulação , Sistema Urogenital/anatomia & histologia , Coelhos/classificaçãoAssuntos
Humanos , Neoplasias Urogenitais , Sistema Urogenital/anatomia & histologia , Sistema Urogenital/embriologia , Sistema Urogenital/fisiologia , Sistema Urogenital/lesões , Urologia/educação , Urologia/métodos , Desenvolvimento Sexual , Doenças Urológicas , Infecções Sexualmente Transmissíveis , Saúde ReprodutivaAssuntos
Humanos , Biologia/educação , Células/ultraestrutura , Histologia/educação , Sistema Digestório/anatomia & histologia , Sistema Respiratório/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Técnicas Histológicas/métodos , Hematopoese , Olho/anatomia & histologia , Pele/anatomia & histologia , Sistema Cardiovascular/anatomia & histologia , Sistema Endócrino/anatomia & histologiaAssuntos
Humanos , Anatomia/educação , Anatomia/métodos , Fisiologia/educação , Fisiologia/métodos , Histologia/educação , Sistema Linfático/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Sistema Cardiovascular/anatomia & histologia , Sistema Digestório/anatomia & histologia , Sistema Musculoesquelético/anatomia & histologia , Sistema Nervoso/anatomia & histologia , Sistema Respiratório/anatomia & histologia , Tegumento Comum/anatomia & histologiaRESUMO
The morphological and histological features of the unusual reproductive tract of the female lesser anteater, Tamandua tetradactyla (Myrmecophagidae, Xenarthra), are described for the first time. The present study aimed to establish the main similarities and differences between this species and other xenarthrans. The populations of this species are declining rapidly for a number of reasons and our study is relevant to diverse programs related to its conservation. Studies were carried out on five female genital tracts of adult specimens. Ovaries were ovoid, presenting a medulla completely surrounded by the cortex, differently from that described in other xenarthans. Like in Dasypus but different from all other armadillos studied, single oocyte follicles were observed and a simple the uterus. The uterovaginal canal connects the uterus with the urogenital sinus. The simple columnar epithelium of the uterovaginal canal ends abruptly at a septum which resembles a hymen, where the transitional epithelium of the urogenital sinus appears. This ancestral feature is shared with that of other armadillos, except Tolypeutes matacus, which has a true vagina. Characteristics of the reproductive tract and sperm morphology of other Xenarthra are comparatively discussed. These observations suggest that important reproductive features are shared between the family Myrmecophagidae and the genus Dasypus, a basal group in the phylogeny of Xenarthra.
Assuntos
Genitália Feminina/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Xenarthra/anatomia & histologia , Animais , Feminino , Ovário/anatomia & histologia , Oviductos/anatomia & histologia , Útero/anatomia & histologiaRESUMO
The anatomy, histology and androgen receptor immunohistochemistry of the prostate (P), seminal vesicles (SV), bulbourethral and coagulant gland (CG) were studied in male viscacha, a seasonally reproductive wild rodent. Two histologically well-defined zones, peripheral and central, were identified in the prostate, according to their relationship with the urethra. The epithelial cells were periodic acid-Schiff (PAS)-positive in the central zone and alcian blue negative in the two zones. The SV are a paired gland, tubular, of tortuous aspect and formed by radial layers. The bulbourethral glands were paired, formed by tubuloalveolar acini and surrounded by a thick layer of skeletal muscle. The CG was multilobulated. The large adenomers showed PAS-positive epithelium and were negative to alcian blue. Androgen receptors in the P, SV and coagulating gland showed variations in their distribution with immunohistochemistry heterogeneous pattern. Finally, the reproductive system accessory glands of male viscacha may be considered as a novel and interesting model for the study of seasonal reproduction in photoperiod-dependent animals.
Assuntos
Glândulas Bulbouretrais/anatomia & histologia , Próstata/anatomia & histologia , Receptores Androgênicos/análise , Roedores/anatomia & histologia , Glândulas Seminais/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Animais , Glândulas Bulbouretrais/química , Células Epiteliais , Imunofluorescência , Masculino , Fotoperíodo , Próstata/química , Receptores Androgênicos/imunologia , Glândulas Seminais/química , Coloração e Rotulagem , Uretra/anatomia & histologia , Sistema Urogenital/químicaRESUMO
O crescimento da caprinocultura tem tornado importante o estudo dos aspectos reprodutivos de machos e fêmeas, uma vez que o entendimento da morfofisiologia da reprodução destes animais pode possibilitar um melhor aproveitamento reprodutivo dos mesmos. Sendo assim, o objetivo do presente artigo foi de realizar uma revisão de literatura sobre os aspectos reprodutivos de fêmeas e machos caprinos.
The growth of goat breeding has become the study of reproductive aspects of goats and bucks important, since the understanding of reproductive morphology and physiology of these animals may enable a better use of them. Therefore, the aim of this paper was to accomplish a revision about reproductive aspects of male and female goats.
Assuntos
Reprodução/fisiologia , Espermatozoides/fisiologia , Cabras/fisiologia , Folículo Ovariano/fisiologia , Sistema Urogenital/anatomia & histologiaAssuntos
Humanos , Masculino , Feminino , Sistema Nervoso/anatomia & histologia , Sistema Musculoesquelético/anatomia & histologia , Articulações/anatomia & histologia , Coração/anatomia & histologia , Vasos Sanguíneos/anatomia & histologia , Sistema Digestório/anatomia & histologia , Sistema Urogenital/anatomia & histologia , Sistemas Neurossecretores/anatomia & histologiaRESUMO
The urogenital ridge (which includes the gonad and attached mesonephros) has proved to be a unique system to analyze the role of vascularization in morphogenesis of an internal organ. During the period of vascularization, development of the testis and ovary diverge morphologically. Time-lapse imaging of the gonad provides novel insights into the mechanisms that incorporate vasculature into an organ at the stage when structural organization of the tissue is initiated. Moreover, the divergent development of the testis and ovary provides a basis of comparison to correlate vascular development with the sex specific morphological development of the tissue. We are currently incorporating different cellular markers in this analysis to simultaneously image the endothelium and other cells in the organ. As far as we know, this is the first system for imaging vascular development in an organ undergoing extensive epithelial morphogenesis (Coveney et al., 2008). We are optimistic that this work will lead to further insights into the interwoven processes of cell differentiation and paracrine signaling that transform a common bipotential primordium to the highly specialized testis or ovary.(AU)
Assuntos
Sistema Urogenital/irrigação sanguínea , Sistema Urogenital/anatomia & histologia , Endotélio Vascular/crescimento & desenvolvimento , Gônadas/crescimento & desenvolvimento , Diagnóstico por Imagem , Fatores de Crescimento do Endotélio Vascular/fisiologia , Ovário/crescimento & desenvolvimento , Testículo/crescimento & desenvolvimentoRESUMO
The urogenital ridge (which includes the gonad and attached mesonephros) has proved to be a unique system to analyze the role of vascularization in morphogenesis of an internal organ. During the period of vascularization, development of the testis and ovary diverge morphologically. Time-lapse imaging of the gonad provides novel insights into the mechanisms that incorporate vasculature into an organ at the stage when structural organization of the tissue is initiated. Moreover, the divergent development of the testis and ovary provides a basis of comparison to correlate vascular development with the sex specific morphological development of the tissue. We are currently incorporating different cellular markers in this analysis to simultaneously image the endothelium and other cells in the organ. As far as we know, this is the first system for imaging vascular development in an organ undergoing extensive epithelial morphogenesis (Coveney et al., 2008). We are optimistic that this work will lead to further insights into the interwoven processes of cell differentiation and paracrine signaling that transform a common bipotential primordium to the highly specialized testis or ovary.