Cloning and expression analysis of wpHSP90 gene from Whitmania pigra at different temperatures / 中国中药杂志

HSP90 is a widely distributed molecular chaperone that participates in a variety of cellular processes and plays an important role in the meiosis of germ cells. However, its role in the gonadal development of hermaphroditic Whitmania pigra is not yet clear. To explore the effect of HSP90 on the germ cell development of Wh. Pigra, this study cloned the wpHSP90 gene, performed bioinformatics analysis, and measured its expression levels. The results showed that the cloned wpHSP90 was 2 592 bp in length, with an open reading frame(ORF) of 2 373 bp, encoding 790 amino acids. Prediction analysis revealed 85 phosphorylation modification sites on serine, threonine, and tyrosine residues of the wpHSP90 protein. Structural domain prediction and multiple sequence alignment results showed that wpHSP90 contained two conserved domains of HSP90 and exhibited the highest homology with Helobdella robusta, with a sequence similarity of 80.72%. RT-qPCR results showed that the relative expression level of wpHSP90 in the gonads of 5-month-old Wh. pigra was positively correlated with temperature within the range of 12 ℃ to 28 ℃. The expression level in the female gonads was significantly higher than in the male gonads and correlated with the trend of germ cell development in the ovaries and testes. In conclusion, wpHSP90 may be involved in regulating the development of germ cells, particularly oocytes, in Wh. pigra. This study provides a reference for further research on the gonadal development mechanism in Wh. pigra.

Clinical Characterization of Patients with Ovarian Mass Combined with Dysplasia of Secondary Sexual Characteristics / 中国医学科学院学报

Objective To investigate the clinical characteristics of preadolescent and adolescent female patients with ovarian mass combined with dysplasia of secondary sexual characteristics. Methods This study retrospectively analyzed 18 cases of ovarian mass combined with dysplasia of secondary sexual characteristics aged 0-19 years admitted to Peking Union Medical College Hospital from January 2012 to November 2019.By analyzing the clinical manifestations,surgical methods,postoperative pathology,therapies and prognosis of the cases,we summarized the diagnosis and treatment ideas. Results Among the 18 cases,7(7/18,38.9%)developed secondary sex signs before puberty,including 5 cases showing precocity(including 2 cases of juvenile granulosa cell tumor,1 case of gonadoblastoma,1 case of ovarian follicular cyst,and 1 case of 46,XY simple gonadal dysplasia combined with dysgerminoma)and 2 cases presenting masculine manifestations(1 case of steroid cell tumor and 1 case of sclerosing stromal tumor).The rest 11(11/18,61.1%)cases showed abnormal development of secondary sexual characteristics during puberty,including 8 cases with masculine manifestations or abnormal menstruation after menarche(7 cases with sex cord stromal cell tumor and 1 case with cystic granulosa cell tumor),2 cases with primary amenorrhea(1 case with androgen insensitivity syndrome combined with testicular sertoli cell tumor and 1 case with endometriosis cyst combined with reproductive tract malformation),and 1 case diagnosed as 46,XX gonadal dysplasia with serous cystadenoma and no secondary sexual development during puberty. Conclusions Sex hormone levels should be actively tested in the case of prepubertal secondary sexual characteristics appearing early,pubertal secondary sexual characteristics being abnormal(underdevelopment),and/or menstrual abnormalities.Imaging examination should be performed to exclude ovarian organic lesions,and chromosome karyotype analysis should be performed if necessary.The diagnosis of ovarian mass in preadolescent and adolescent females with related symptoms should first be alerted to cord stromal cell tumor.It is recommended to rule out the possibility of combined reproductive tract malformation in the adolescent patients with primary amenorrhea.Chromosome examination should be conducted to rule out the possibility of gonadal dysplasia in the adolescent patients with primary amenorrhea and/or no development of secondary sexual characteristics.

Gonadal maturation in Pseudoplatystoma metaense x Leiarius marmoratus hybrids, (Siluriformes: Pimelodidae) / Maduración gonadal en híbridos de Pseudoplatystoma metaense x Leiarius marmoratus (Siluriformes: Pimelodidae)

SUMMARY: Establishing guidelines for responsible management in fish production systems requires knowledge of the basic biology of the fish to be raised. The objective of this work was to determine the reproductive capacity of hybrids produced from the crossing of females of Pseudoplatystoma metaense with males of Leiarius marmoratus. Males presented a digitiform, unrestricted spermatogonial testicle containing caudal digits producing glycoproteins that do not form a seminal vesicle. It was possible to find free sperm in the lumen of the tubules and in the ducts. The ovary of the females was found to be saccular and synchronous with at least three groups of oocytes. In the first year of life, only oogonia up to previtellogenic oocytes (cortical alveolus 284.9 ± 35.7 mm in diameter) were found. After the second year vitellogenic oocytes 730 ± 3.78 mm in diameter were observed. The events of gonadal development of the hybrids indicate that they are gonochoric, synchronic animals. The maturation peaks in the high-water season, overlapping with the parental species. Therefore, the escape of hybrids from fish cultures to the rivers may increase the risk of crosses, gene introgression, or diminution of the reproductive capacity of the pure species.

RESUMEN: El establecimiento de pautas para la gestión responsable en los sistemas de producción de peces requiere el conocimiento de la biología básica de los peces a criar. El objetivo de este trabajo fue determinar la capacidad reproductiva de los híbridos producidos por el cruce de hembras de Pseudoplatystoma metaense con machos de Leiarius marmoratus. Los machos presentaron un testículo espermatogonial digital no restringido que contiene dígitos caudales que producen glucoproteínas que no forman una vesícula seminal. Fue posible encontrar esperma libre en la luz de los túbulos y en los conductos. Se encontró que el ovario de las hembras era sacular y sincrónico con al menos tres grupos de ovocitos. En el primer año de vida, solo se encontraron oogonia hasta ovocitos previtelogénicos (alvéolo cortical de 284,9 ± 35,7 mm de diámetro). Después del segundo año, se observaron ovocitos vitelogénicos de 730 ± 3,78 mm de diámetro. Los eventos de desarrollo gonadal de los híbridos indican que son animales sincrónicos gonocóricos. La maduración alcanza su punto máximo en la temporada de aguas altas, superponiéndose con las especies parentales. Por lo tanto, el escape de híbridos de cultivos de peces a los ríos puede aumentar el riesgo de cruces, introgresión genética o disminución de la capacidad reproductiva de las especies puras.

Effects of MT on growth and gonad development of natural overwintering Whitmania pigra / 中国中药杂志

The objectives of study were to explore the effects of exogenous methyltestosterone( MT) on the growth and gonadal development of overwintering Whitmania pigra. Before overwintering,0. 1,1. 0,10. 0,100. 0,150. 0 μg·L-1 of MT were added to the aquaculture water for 6 weeks. The changes of growth performance,gonad index,endogenous steroid hormones level and internal quality were measured after hibernate for 60 days. Then the tissue slice technique was used to observe the spermary( ovary) of Wh. pigra.The results showed that the body weight,survival rate and gonadal index increased first and then decreased with the increase of exogenous MT concentration; the male gland index was found the highest at the concentration of MT 10. 0 μg·L-1 and the female gland index was the highest at the concentration of MT 1. 0 μg·L-1. The survival rate of Wh. pigra peaked at the concentration of MT 10. 0 μg·L-1.The weight reaches a peak at a concentration of MT 100. 0 μg·L-1( P<0. 05). The number of primary spermatocytes in the testis was negatively correlated with the concentration of exogenous MT. The number of secondary spermatocytes and sperm cells increased first and then decreased. The concentration of secondary spermatocytes was the highest when the concentration of MT was 100. 0 μg·L-1.The number and volume of oocytes in the ovary and the yolk granules increased first and then decreased with the increase of exogenous MT concentration,and the highest was observed at the MT concentration of 100. 0 μg·L-1. The endogenous steroid hormone of Wh.pigra increased first and then decreased with the increase of exogenous MT concentration. The concentration of androgen and progesterone was the highest in MT 100. 0 μg·L-1 treatment( P<0. 05),and the concentration of estrogen was found the highest in MT 10. 0 μg·L-1 treatment( P<0. 05). After adding exogenous MT,Wh. pigra moisture content,acid-insoluble ash content,p H and anti-thrombin activity met the quality criterion of medicinal Wh. pigra in Chinese Pharmacopoeia( 2015 edition). In conclusion,the short-term addition of 1. 0-100. 0 μg·L-1 exogenous MT before hibernation can promote the growth,the development of sperm cells and the antithrombin activity of Wh. pigra.

Genetic etiology of 46, XY complete gonadal dysgenesis / 国际儿科学杂志

46,XY complete gonadal dysgenesis (46,XY CGD) is a rare congenital genetic disease.Individuals with 46,XY CGD are characterized by female external genitalia,Müllerian duct structures and streak gonads.The pathogenesis of this disease is complex,which is related to the variation of sex determination genes in humans.In addition to the classic genes SRY,SOX9 and NR5A1,it has been found that the disease can be caused by the signal pathways such as DHH and MAPK,as well as other regulatory factors such as ubiquitination in recent years.However,only less than 50％ of patients receive an accurate clinical genetic diagnosis.Facilitated by ongoing developments in genetic sequencing technologies,more and more potential pathogenic genes have been discovered,enriching the gene regulatory network of sex determination.The proper and prompt diagnosis and treatment of 46,XY CGD are always challenging,given the low rate of diagnosis and the risk of gonadal malignancy,which are imperative for long-term management of the individuals.Recently,great progress has been made in the study of 46,XY CGD both at home and abroad.

Effects of 17β-E2 on growth and gonad development of overwintering Whitmania pigra / 中国中药杂志

The present study was conducted to explores the effects of short-term addition of 17β-E2 on the growth,gonad development and internal quality of overwintering Whitmania pigra. Before overwintering,0. 0,1. 0,10. 0,25. 0,50. 0,100. 0 μg·L~(-1) of 17β-E2 were added to the aquaculture water for 6 weeks and then hibernated for 60 days. The changes of growth performance,gonad index,morphological structure of spermary( ovary),endogenous steroid hormones level and internal quality were measured. The results showed that the body weight,weight gain rate,specific growth rate,female gonad index,oocyte development and endogenous estrogen level of the leech increased first and then decreased with the increase of the concentration of exogenous 17β-E2,which were higher than those of the control group. The body weight,weight gain rate and specific growth rate of the leech at the concentration of 25 μg·L~(-1)17β-E2 were significantly higher than those of the other groups( P<0. 05),oocyte development and endogenous estrogen levels were significantly higher than those of other groups at the concentration of 50 μg·L~(-1)( P<0. 05). When the concentration of exogenous 17β-E2 was higher than 50 μg·L~(-1),the levels of male gonad index,spermatocyte development,endogenous androgen and progesterone were significantly inhibited( P< 0. 05). There was no significant difference in endogenous corticosteroid levels among the groups. In conclusion,short-term addition of exogenous 17β-E2 of 10-25 μg·L~(-1) could promote the growth of overwintering leeches,oocyte development and antithrombin activity without inhibiting the development of male gonads.

El adelanto en la telarquia y edad de la menarquia se relacióna con la malnutrición por exceso en niñas chilenas pero no en varones: estudio de base poblacional / The advance in thelarche and age of menarche is related to malnutrition by excess in Chilean girls but not in boys: population-based study

Introduction: Puberty normally begins after 8 years in girls and 9 years in boys. Objective: To determine the prevalence of signs of precocious puberty (PP), breast development in girls, premature gonadal development (PGD), premature adrenarche (PA), menarche age (MA) and its association with nutritional status (NS). Material and Methods: From a sample of 3.010 children from 5 to 14 years randomly selected in Santiago of Chile were chosen a subsample of 873 kids according to the cutoff to define PP. Survey was applied to obtain MA. Logistic regression were used to evaluate the relationship between PP and NS. Results: In boys the prevalence of PGD and PP was 8.55% and 3.16% respectively, no relationship was found with nutritional status In girls the prevalence of breast development and PA was 8.13% and 0.9% respectively. Only there be association between PP and NS in women: with a prevalence of 1,2%, 13,9% and 21,1% in well-nourished, Overweight and obesity are at greater risk of showing PP compared with eutrophic girls with an OR of 25,5 (IC 95% 3,2-203,0) and 46.93 (IC 95% 6,1-361,5). MA was 12,01 ± 0,94 years in eutrophic girls and 11,40 ± 0,96years in obese girls (p< 0,05). Conclusion: There was a positive correlation in females between overweight and obesity an PP and MA. There is a secular trend in MA, to compare these findings with other national studies. Obesity could have an important role in explaining the advancement observed in pubertal development.

Introducción: El desarrollo puberal se inicia normalmente después de los 8 años en niñas y de los 9 años en varones. Objetivo: Estimar la prevalencia de signos de pubertad precoz (sPP): crecimiento genital (CG) en varones, telarquia en niñas y vello púbico (VP) en ambos sexos; y determinar edad de la menarquia (EM) en una muestra de escolares de Santiago de Chile), y evaluar la asociación de estas variables con el estado nutricional (EN). Material y Métodos: Se examinaron 3.010 escolares de clase media baja de 6 a 14 años, pertenecientes a 10 colegios de Santiago de Chile y seleccionados aleatoriamente. En todos ellos se consignó peso, talla, IMC y desarrollo puberal según Tanner. Se aplicó una encuesta a los padres para obtener la EM a la población total de mujeres (n= 1.433). Para determinar sPP se analizaron por separado los 867 niños (62% mujeres) menores a la edad establecida como puntos de corte para definir PP. Se utilizó regresión logística para determinar la asociación existente entre sPP y el EN. Resultados: En varones la prevalencia de CG y VP fue de 8,55% y 3,16% y no se asocio al EN. La prevalencia de telarquia y VP en niñas fue de 8,13% y 0,9% respectivamente. Se observó una fuerte asociación entre telarquia y EN con prevalencias de 1.2%, 13.9% y 21.1% en eutróficas, sobrepeso y obesas, respectivamente (p< 0,0001) (Gráfico 1). La presencia de sobrepeso y/o obesidad otorgan un mayor riesgo de presentar telarquia, vs comparación con las niñas eutróficas con un OR de 25,5 (IC 95% 3,2-203,0) y 46.93 (IC 95% 6,1-361,5), respectivamente. La EM fue 12,01 ± 0,94 años en niñas eutróficas siendo de 11,40 ± 0,96 años en niñas obesas (p< 0,05). Conclusión: Se observó una correlación positiva solo en el sexo femenino entre malnutrición por exceso, telarquia precoz y EM. Se observa una tendencia secular en la EM al comparar los hallazgos con otros estudios nacionales.

Descrição morfológica dos ovários do peixe Melanotaenia boesemani em atividade reprodutiva / Morphological description of Melanotaenia boesemani ovaries in reproductive activity

Estudou-se o tecido germinativo ovariano do peixe Melanotaenia boesemani. Por meio de análises morfológicas das gônadas, realizadas após a confecção de lâminas histológicas elaboradas em parafina e coradas com hematoxilina-eosina, foram descritos os tipos celulares encontrados e realizada a classificação do estádio de maturidade dos peixes. Macroscopicamente, foi identificado que a referida espécie possui ovário único, arredondado e, na fase observada, amarelado, localizado na parte látero-anterior da cavidade celomática. As fêmeas analisadas foram classificadas na escala de desenvolvimento gonadal como maduro/em reprodução. A presença de folículos vazios e marcas de desova nas lamelas ovulígeras mostrou-se evidente. Nos ovócitos vitelogênicos deste peixe, foi constatada a presença de filamentos de adesão ovocitária ancorados à zona pelúcida. Os ovários apresentaram aspecto morfológico geral semelhante ao de outros peixes teleósteos. Seu tipo de desova foi classificado como intermitente e o padrão de desenvolvimento de ovócitos, como assincrônico.(AU)

The germinal ovarian tissue of the fish Melanotaenia boesemani was studied. By means of morphological analyses of the gonads, performed after the manufacture of histological slides made of paraffin and stained with hematoxylin-eosin, the cell types found were described and the rank of the maturity stage of the fishes was executed. Macroscopically was found that the species has only one ovary, rounded and in the observed phase yellowish, located in the lateral front part of the coelomic cavity. The observed females were classified in the gonadal development scale as mature/in reproduction. The presence of empty follicles and spawning marks on ovigerous lamellae proved to be evident. In vitellogenic oocytes of this fish, the presence of filaments of oocyte adhesion anchored to the pellucida zona was found. The ovaries showed general morphological appearance similar to that of other teleost fishes. Its spawning type was classified as intermittent and the pattern of development of oocytes as asynchronous.(AU)

Population dynamics of the migratory fish Prochilodus lineatus in a neotropical river: the relationships with river discharge, flood pulse, El Niño and fluvial megafan behaviour

The relative importance of flood pulse dynamics and megafan behaviour for the Sábalo (Prochilodus lineatus) catches in the neotropical Pilcomayo River is studied. The Sábalo catches can mainly be explained by decreased river discharges in the preceding years resulting in smaller inundated areas during rainy season floods and thereby in a decreased area of feeding grounds for the fishes. The decreased river discharges and the related decline of Sábalo catches in the 1990's can be linked to the 90-95 El Niño event. In 2007 the Sábalo catches were comparable to the catches before the "El Niño" event. The connectivity (continuity) between the main river and flood plain areas, which is influenced by sedimentation processes, is also of great importance and very probably plays a more important role since the late 1990's.

Se ha estudiado la importancia relativa de la dinámica del pulso de inundación y el comportamiento del sistema megafan para las capturas del Sábalo (Prochilodus lineatus) en el río Pilcomayo. Las capturas del Sábalo puede explicarse fundamentalmente por los bajos caudales del río en los años anteriores, resultando en menores superficies de las zonas inundadas durante la temporada de lluvia y por lo tanto en una área menor de alimentación para los peces. La disminución del caudal del río y la declinación relativa de capturas de Sábalo en los años 1990 pueden estar relacionadas con el 90-95 evento de El Niño. En 2007, la captura de Sábalo fue comparable a las capturas antes del evento de "El Niño". La conectividad (continuidad) entre el río principal y las llanuras aluviales, que son influenciadas por los procesos de sedimentación, son también de gran importancia y muy probablemente juegan un papel muy importante desde finales de los años '90.

SF-1 gene mutation and gonad development / 国际儿科学杂志

Orphan nuclear receptor steroidogenic factor 1 (SF-1) is a member of the nuclear receptor superfamily. It regulates the expression of multiple genes involved in adrenal and gonadal development,steroidogenesis,and reproductive function. Twenty five different mutations have been described and their clinical features are various. Detection of SF-1 gene may be contribute to the etiological diagnosis for 46, XY disorder of sex development patients.

Histological and histochemical analysis of the gonadal development of males and females of Armases rubripes (Rathbun 1897) (Crustacea, Brachyura, Sesarmidae) / Análise histológica e histoquímica do desenvolvimento gonadal de machos e fêmeas de Armases rubripes (Rathbun, 1897) (Crustacea, Brachyura, Sesarmidae)

The objective of this study was to provide information on the histological characteristics of the gonads of male and female Armases rubripes crabs, and to try to establish a relationship between the microscopic and macroscopic stages previously identified. Thirty-six crabs were collected by hand between February 2003 and January 2004 in banks of Spartina alterniflora on Sahy Beach in Mangaratiba, Rio de Janeiro state, Brazil. The histological analysis of the ovaries of A. rubripes demonstrated a gradual process of development of the oocytes. According to their cellular characteristics, five types of cells were distinguished: oogonia, oocyte I, oocyte II, oocyte III and oocyte IV. The ovaries showed four stages during gonadal activity: stage I (rudimentary), stage II (developing or maturing), stage III (developed or mature) and stage IV (resting). The results of the histochemical analyses showed that the ovaries vary according to the gonad development stage. The histological aspect of one section of the male gonad was always the same in all of the seminiferous tubules, where the lumen of these tubules always contained spermatozoa and/or spermatids. It was not possible to characterize the three stages of gonad development in the males. This agrees with previous reports in the literature. However, in the females there was a relationship between the gonad stages distinguished macroscopically and the results obtained through the histological and histochemical analysis, due to the presence of different cell types, as well as the lysis process and reabsorption of the oocytes in spent females.

O objetivo deste estudo foi fornecer informações sobre as características histológicas das gônadas de machos e de fêmeas de Armases rubripes, tentando estabelecer uma relação entre os estágios microscópicos e os macroscópicos anteriormente identificados. Foram coletados manualmente 36 caranguejos, durante o período de fevereiro de 2003 a janeiro de 2004, em bancos de Spartina alterniflora na praia do Sahy Mangaratiba, Estado do Rio de Janeiro. A análise histológica dos ovários de A. rubripes demonstrou um processo gradual de desenvolvimento dos oócitos. De acordo com sua característica celular, cinco tipos de células foram distinguidos: ovogônias, oócito I, oócito II, oócito III, oócito IV. Os ovários revelaram quatro estágios de atividade gonadal: estágio I (rudimentar), estágio II (em desenvolvimento ou em maturação), estágio III (desenvolvido ou maduro), estágio IV (desovada). Os resultados das análises histoquímicas permitem afirmar que os ovários variam de acordo com o estágio de desenvolvimento gonadal. O aspecto histológico de uma sessão de gônada masculina é sempre o mesmo em todos os túbulos seminíferos, onde o lúmen deste túbulo sempre contém espermatozóides e/ou espermátides. Não foi possível a caracterização de três estágios de desenvolvimento gonadal em machos, conforme descrito previamente na literatura. Entretanto, em fêmeas, houve uma relação entre os estágios gonadais distinguidos macroscopicamente e os resultados obtidos através da análise histológica e histoquímica, devido à presença de diferentes tipos celulares, assim como processo de lise e reabsorção dos oócitos em fêmeas desovadas.

Desenvolvimento gonadal de fêmeas de matrinxã, Brycon amazonicus, submetidas a restrição alimentar / Gonadal development of matrinxã, Brycon amazonicus, females submitted to feed restriction

O presente estudo avaliou o efeito de ciclos de restrição alimentar e realimentação (2/3 dias), aplicados durante seis meses antes da desova, no desenvolvimento gonadal de matrinxã. Na ocasião da desova, fêmeas alimentadas diariamente e submetidas ao regime alimentar experimental, selecionadas para a indução hormonal, foram sacrificadas para retirada das gônadas e do fígado, com os quais se calculou o IGS (índice gonadossomático) e o IHS (índice hepatossomático), sendo os ovários processados para análise histológica. Não houve alteração no peso relativo dos ovários e fígado, e o desenvolvimento gonadal não foi afetado pelo esquema alimentar. Os valores de IGS foram de 5,09±4,98 por cento e 9,79±4,17 por cento e os de IHS foram de 0,84±0,07 por cento e 0,91±0,11 por cento, para as fêmeas controle e experimentais, respectivamente, sem diferenças significativas entre os grupos. Os ovários de peixes dos dois grupos apresentaram as mesmas características do estádio maduro, com predominância de ovócitos na fase final de maturação, repletos de vitelo. O estudo indica que a restrição alimentar não afetou a preparação das fêmeas para a reprodução e que ciclos adequados de restrição e realimentação poderão ser aplicados na criação do matrinxã, assegurando menores custos de produção.

The present study evaluated the effect of cycles of feed restriction and refeeding (2/3 days) during 6 months before the spawning on the gonadal development of matrinxã. At the spawning time, females selected to hormonal induction were killed for gonad and liver removal and GSI (gonadosomatic index) and HSI (hepatosomatic index) were calculated. Ovaries were processed for histological analysis. The feeding regime did not alter GSI and HSI and the gonadal development. The values of GSI were 5.09±4.98 percent and 9.79±4.17 percent, and of HSI were 0.84±0.07 percent and 0.91±0.11 percent, in control and experimental females, respectively, without significant difference between groups. Ovaries from both fish groups showed the same charachteristics of the mature stage, with predominance of oocytes in the final phase of maturation, presenting large amount of yolk. The study indicates that the feed restriction did not affect the matrinxã ability to reproduction and that cycles of feed restriction and refeeding can be used in matrinxã farming leading to lower production costs.

Desenvolvimento morfológico dos ovários em fetos eqüinos sem raça definida / Morphological development of ovaries in fetuses of cross-breed equines

O objetivo deste trabalho foi caracterizar histologicamente o desenvolvimento ovariano pré-natal em fetos eqüinos sem raça definida (SRD) nos trópicos, ressaltando surgimento e quantificação de ovogônias e folículos. Foram obtidos 131 fetos em frigorífico, os quais foram mensurados quanto ao comprimento (cm) equivalente à distância cefalococcígea (CR), seguido de corte das gônadas e fixação das amostras em Bouin por 24 horas. As idades foram estimadas por regressão. Foram preparados cortes histológicos ovarianos de 7µm de espessura, os quais foram corados com hematoxilina-eosina. O surgimento de ovogônias, folículos primordiais, em crescimento e antrais foi verificado, respectivamente, em fetos com CR entre 4,1 e 6,5cm (40 a 49 dias de gestação (DG)); 9,1 e 12,0cm (60 a 69 DG); 23,1 e 29,0cm (116 a 135 DG) e 50,1 e 65,0cm (201 a 245 DG). A quantidade máxima de ovogônias, folículos primordiais, em crescimento e antrais foi observada em fetos com CR entre, 4,1 e 6,0cm (40 a 49 DG); 16,1 e 23,0cm (90 a 115 DG); 29,1 e 36,0cm (136 a 155 DG) e 50,1 e 97,0cm (201 a 320 DG), respectivamente. Os resultados sugerem que o desenvolvimento morfológico dos ovários fetais de eqüinos SRD nos trópicos é mais precoce que o observado nos relatos de literatura referentes a estudos de eqüinos de diversas raças em regiões temperadas.

This research research was aimed at histologically characterizing the pre-natal ovarian development of cross-breed equine fetuses in the tropics, observing the rise and the quantification of oogonia and follicles. One hundred and thirty one fetuses were obtained from a slaughterhouse, their crown-rump length (CRL) was measured in centimeters (cm). Next, the gonads were sectioned and the samples were placed to rest in Bouinïs liquid for 24 hours. The ages were estimated by regression. 7µm thick histological ovarian cuts were prepared and stained with hematoxylin-eosin. Oogonia, primordial, growing and antral follicles were observed in fetuses whose CRL was between 4.1 and 6.5cm (40 to 49 gestation days (GD)); 9.1 and 12.0cm (60 to 69 GD); 23.1 and 29.0cm (116 to 135 GD); 50.1 and 65.0cm (201 to 245 GD) respectively. The maximum amount of oogonia and of primordial, growing and antral follicles occurred in fetuses whose CRL was between 4.1 and 6.0cm (40 to 49 GD); 16.1 and 23.0cm (90 to 115 GD); 29.1 and 36.0cm (136 to 155 GD); 50.1 and 97.0cm (201 to 320 GD), respectively. These results suggest that the development of cross-breed equine ovarian fetuses in the tropics is more premature than that described in the literature on studies of various equine breeds in temperate regions.