Post-larval morphology, growth, and development of Uca cumulanta Crane, 1943 (Crustacea, Decapoda, Ocypodidae) under laboratory conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Does the male reproductive performance depend on the early lactation milk in rats?

This study investigated the role of the early lactation milk (ELM) on the male reproductive performance and the participation of GnRH on this effect in Wistar rats. Newborn males were divided into three experimental groups: 1) ELM-deprived pups, 2) ELM-deprived pups treated with exogenous GnRH 1, 7, 25, and 31 h after birth, and 3) non-ELM-deprived and without exogenous GnRH. In relation to the other two groups, the ELM-deprived male rats exhibited as adults: reduced fertility, decreased weight of both vas deferens and seminal vesicle, and reduced levels of fructose in the seminal vesicle and prostate gland. We suggest that the intake of ELM during the neonatal period is important to the later sexual development of rats, and that GnRH is somehow involved in such an effect.

Reproductive changes in male rats treated perinatally with an aromatase inhibitor.

The effects of maternal exposure to aromatase inhibitor during the perinatal period of sexual brain differentiation were studied. The fertility was assessed in adult, male rat offspring of aromatase inhibitor-treated dams. The following results were obtained: (1) Sexual maturation, body weight, and wet weights of testis, pituitary, seminal vesicle, ventral prostate, and levatori ani muscle were unchanged at adult life. (2) Fifty percent of the animals were able to mate with normal females, which became pregnant but exhibited an increased number of preimplantation loss. (3) There was a decrease in the number of spermatozoa found in the testes and in the daily sperm production. (4) Of those, 25% of the male rats treated with aromatase inhibitor did not present male sexual behavior, showing female behavior when pretreated with estrogen. These results indicate that perinatal exposure to aromatase inhibitor during the critical period of male brain sexual differentiation has a long-term effect on the reproductive physiology and behavior of male rats.

Neonatal inhalatory anesthetic exposure: Reproductive changes in male rats

We investigated the effects of an inhalatory anesthetic (ethyl ether) during the neonatal period of brain sexual differentiation on the later fertility and sexual behavior of male rats. Animals were exposed to ethyl ether immediately after birth. At adulthood, body weight, testes wet weight, and plasma testosterone levels were not affected; however, neonatal exposure to ether showed alterations on male fertility: a decrease in the number of spermatids and spermatozoa, an increase in the transit time of cauda epididymal spermatozoa and a decrease in daily sperm production. An alteration of sexual behavior was also observed: decreased male sexual behavior and appearance of homosexual behavior when the male rats were castrated and pretreated with exogenous estrogen. Probably, the ether delayed or reduced the testosterone peak of the sexual differentiation period, altering the processes of masculinization and defeminization of the hypothalamus. Our results indicate that perinatal exposure to ethyl ether during the critical period of male brain sexual differentiation, acting as endocrine disruptors, has a long-term effect on the fertility and sexual behavior of male rats, suggesting endocrine disruption through incomplete masculinization and defeminization of the central nervous system. © 2002 Elsevier B.V. All rights reserved.

Long-term effects of perinatal androgenization on reproductive parameters of male rat offspring androgenization and male rat reproduction

It is known that during sex differentiation, fetal androgens are critical determinants of the male phenotype. Although testosterone is necessary for normal development of male sexual behavior, perinatal androgen treatment can result in disruption of normal male sexual reproduction. Pregnant Wistar rats were administered either corn oil (vehicle) or testosterone propionate at 0.2 mg/kg from gestational day 12 until the end of lactation and the reproductive function of male offspring was evaluated at 90 (adulthood) and 270 (middle age) days of age. Perinatal androgenization in the rat provoked a reduction in sperm production and reserves in adulthood that did not affect fertility and did not persist at more advanced ages, as shown by the results at post-natal day 270. If perinatal androgenization promotes similar effects in humans of reproductive age, the results of the present work can impact male reproduction health, given the less efficient spermatogenesis and lower sperm reserves in the human epididymis, compared to rodents. © Georg Thieme Verlag KG Stuttgart. New York.

The discovery of Foxl2 paralogs in chondrichthyan, coelacanth and tetrapod genomes reveals an ancient duplication in vertebrates

The Foxl2 (forkhead box L2) gene is an important member of the forkhead domain family, primarily responsible for the development of ovaries during female sex differentiation. The evolutionary studies conducted previously considered the presence of paralog Foxl2 copies only in teleosts. However, to search for possible paralog copies in other groups of vertebrates and ensure that all predicted copies were homolog to the Foxl2 gene, a broad evolutionary analysis was performed, based on the forkhead domain family. A total of 2464 sequences for the forkhead domain were recovered, and subsequently, 64 representative sequences for Foxl2 were used in the evolutionary analysis of this gene. The most important contribution of this study was the discovery of a new subgroup of Foxl2 copies (ortholog to Foxl2B) present in the chondrichthyan Callorhinchus milii, in the coelacanth Latimeria chalumnae, in the avian Taeniopygia guttata and in the marsupial Monodelphis domestica. This new scenario indicates a gene duplication event in an ancestor of gnathostomes. Furthermore, based on the analysis of the syntenic regions of both Foxl2 copies, the duplication event was not exclusive to Foxl2. Moreover, the duplicated copy distribution was shown to be complex across vertebrates, especially in tetrapods, and the results strongly support a loss of this copy in eutherian species. Finally, the scenario observed in this study suggests an update for Foxl2 gene nomenclature, extending the actual suggested teleost naming of Foxl2A and Foxl2B to all vertebrate sequences and contributing to the establishment of a new evolutionary context for the Foxl2 gene. © 2013 Macmillan Publishers Limited All rights reserved.

Diferenças de gêneros nos grupos de brincadeira na rua: a hipótese de aproximação unilateral

Este estudo investigou aspectos da diferenciação sexual em brincadeiras de crianças/adolescentes na rua. Participaram 668 pessoas entre 1 e 18 anos (245 meninas – 423 meninos), moradores/visitantes de três ruas num bairro da periferia de Belém, durante 1 ano. Foram observadas diferenças de gênero quanto à participação na rua e à variedade de subcultura lúdica. Observou-se predominância dos meninos na rua, segregação e tipificação sexual nas brincadeiras e maior penetração das meninas na subcultura masculina. Os dados sobre composição dos grupos, segregação, tipificação e preferência por brincadeiras levam à hipótese de aproximação unilateral entre os grupos de gênero.

Habilidades sociais em portadores de anomalia da diferenciação sexual

O termo Habilidades Sociais (HS) é usado para designar um conjunto de repertórios comportamentais que envolvem interações sociais satisfatórias. A maioria dos estudos publicados sobre essa temática inclui a participação de crianças e adolescentes, abordando situações em ambiente escolar. Poucos são os estudos voltados para a área de saúde, e, até o momento, não foram localizadas pesquisas sobre HS realizadas com indivíduos portadores de Anomalia da Diferenciação Sexual (ADS). Esta anomalia se caracteriza pela malformação na genitália e/ou pela disfunção das gônadas, ocasionando características sexuais secundárias não correspondentes ao sexo de criação. Estudos clínicos realizados com indivíduos portadores de ADS têm destacado a ocorrência de déficits em habilidades sociais nesses indivíduos, caracterizados pela fuga-esquiva de situações sociais aversivas. Neste trabalho, pretendeu-se caracterizar o repertório comportamental correspondente a HS em indivíduos com ADS atendidos no ambulatório de um programa especializado de um hospital da rede pública de Belém, por meio de dois estudos complementares. No primeiro, foi realizado um estudo com delineamento transversal, com o objetivo de caracterizar comportamentos correspondentes a HS em indivíduos com ADS. Participaram 9 adultos com mais de seis meses em tratamento. Foram utilizados: Roteiro de Entrevista, Protocolo para análise de prontuário e Inventário de Habilidades Sociais - IHS. Os resultados sugerem que os participantes apresentam déficit de habilidades sociais em todos os fatores do IHS em menor ou maior grau, de maneira que poderiam se beneficiar com um treinamento de habilidades sociais como parte do tratamento, por se tratar de uma técnica que visa à superação e/ou redução dos déficits por eles apresentados. No segundo, foi realizado um estudo com delineamento de sujeito único, com o objetivo de verificar os efeitos do uso de treino em automonitoramento na instalação de comportamentos correspondentes a HS. Participou uma adulta com diagnóstico de ADS selecionada dentre os que participaram do Estudo 1. O procedimento de intervenção ocorreu por meio de entrevistas semanais, de acordo com as seguintes etapas: (1) Contrato: assinatura do Termo de Consentimento Livre e Esclarecido e agendamento de entrevista; (2) Avaliação: levantamento da linha de base dos comportamentos correspondentes à HS, elaboração da hierarquia dos comportamentos que indicaram déficit segundo as normas de análise do IHS e treino em registro de automonitoração; (3) Intervenção: leitura de um texto sobre habilidades sociais, apresentação da lista de direitos humanos básicos, aplicação do Questionário Construcional de Goldiamond adaptado e treino em registro de automonitoramento; (4) Re-avaliação das HS: reaplicação do IHS; (5) Follow-up: avaliação da manutenção dos ganhos obtidos com o estudo; e (6) Encerramento: entrevista devolutiva para explanação dos resultados do estudo ao participante. Os resultados sugerem que a intervenção promoveu o desenvolvimento de HS na participante, haja vista a interpretação da evolução da participante apresentada de acordo com a variação do Escore Z e da representação gráfica de significância clínica e mudança confiável.

Inactivating Mutations of the Human Luteinizing Hormone Receptor in Both Sexes

The human luteinizing hormone/chorionic gonadotropin receptor (LHCGR) plays a fundamental role in male and female reproductive physiology. Over the past 15 years, several homozygous or compound heterozygous loss-of-function mutations in the LHCGR gene have been described in males and females. In genetic males, mutations in LHCGR were associated with distinct degrees of impairment in pre- and postnatal testosterone secretion resulting in a phenotypic spectrum. Patients with the severe form of LH resistance have predominantly female external genitalia and absence of secondary sex differentiation at puberty. Patients with milder forms have predominantly male external genitalia with micropenis and/or hypospadias or only infertility without ambiguity. The undermasculization is associated with low basal, as well as human CG-stimulated, testosterone levels and elevated LH levels after pubertal age, without abnormal step-up in testosterone biosynthesis precursors. The testes have only slightly reduced size but mature Leydig cells are absent or scarce (Leydig cell hypoplasia). Genetic females with inactivating LHCGR mutations have female external genitalia, spontaneous breast and pubic hair development at puberty, and normal or late menarche followed by oligoamenorrhea and infertility. Estradiol and progesterone levels are normal for the early to midfollicular phase, but do not reach ovulatory or luteal phase levels. Serum LH levels are high whereas follicle-stimulating hormone levels are normal or only slightly increased. Pelvic ultrasound has demonstrated a small or normal uterus and normal or enlarged ovaries with cysts. The inactivating mutations of the LHCGR have provided important insights into distinct physiological roles of LH in reproduction of both sexes.

Intersex occurrence in rainbow trout (Oncorhynchus mykiss) male fry chronically exposed to ethynylestradiol.

This study aimed to investigate the male-to-female morphological and physiological transdifferentiation process in rainbow trout (Oncorhynchus mykiss) exposed to exogenous estrogens. The first objective was to elucidate whether trout develop intersex gonads under exposure to low levels of estrogen. To this end, the gonads of an all-male population of fry exposed chronically (from 60 to 136 days post fertilization--dpf) to several doses (from environmentally relevant 0.01 µg/L to supra-environmental levels: 0.1, 1 and 10 µg/L) of the potent synthetic estrogen ethynylestradiol (EE2) were examined histologically. The morphological evaluations were underpinned by the analysis of gonad steroid (testosterone, estradiol and 11-ketotestosterone) levels and of brain and gonad gene expression, including estrogen-responsive genes and genes involved in sex differentiation in (gonads: cyp19a1a, ER isoforms, vtg, dmrt1, sox9a2; sdY; cyp11b; brain: cyp19a1b, ER isoforms). Intersex gonads were observed from the first concentration used (0.01 µg EE2/L) and sexual inversion could be detected from 0.1 µg EE2/L. This was accompanied by a linear decrease in 11-KT levels, whereas no effect on E2 and T levels was observed. Q-PCR results from the gonads showed downregulation of testicular markers (dmrt1, sox9a2; sdY; cyp11b) with increasing EE2 exposure concentrations, and upregulation of the female vtg gene. No evidence was found for a direct involvement of aromatase in the sex conversion process. The results from this study provide evidence that gonads of male trout respond to estrogen exposure by intersex formation and, with increasing concentration, by morphological and physiological conversion to phenotypic ovaries. However, supra-environmental estrogen concentrations are needed to induce these changes.

Endogenous expression of Müllerian inhibiting substance in early postnatal rat Sertoli cells requires multiple steroidogenic factor-1 and GATA-4-binding sites

Müllerian inhibiting substance (MIS) is a key element required to complete mammalian male sex differentiation. The expression pattern of MIS is tightly regulated in fetal, neonatal, and prepubertal testes and adult ovaries and is well conserved among mammalian species. Although several factors have been shown to be essential to MIS expression, its regulatory mechanisms are not fully understood. We have examined MIS promoter activity in 2-day postnatal primary cultures of rat Sertoli cells that continue to express endogenous MIS mRNA. Using this system, we found that the region between human MIS−269 and −192 is necessary for full MIS promoter activity. We identified by DNase I footprint and electrophoretic mobility-shift analyses a distal steroidogenic factor-1 (SF-1)-binding site that is essential for full promoter activity. Mutational analysis of this new distal SF-1 site and the previously identified proximal SF-1 site showed that both are necessary for transcriptional activation. Moreover, the proximal promoter also contains multiple GATA-4-binding sites that are essential for functional promoter activity. Thus multiple SF-1- and GATA-4-binding sites in the MIS promoter are required for normal tissue-specific and developmental expression of MIS.

Diferenciación sexual del lenguado de California Paralichthys californicus y control de la proporción sexual mediante la utilización de la hormona 17β-estradiol

El lenguado de California Paralichthys californicus es una especie con alto valor comercial debido a su gran tamaño y calidad de su carne. Esta especie presenta dimorfismo sexual en el crecimiento donde las hembras crecen más rápido que los machos, por lo tanto el cultivo monosexual de hembras resulta favorable para la producción. En el presente estudio se registró el proceso de diferenciación sexual mediante cortes histológicos de las larvas y gónadas del lenguado de California asimismo se probó el efecto de diferentes concentraciones de 17β-estradiol (E2) (2.5, 5 y 10 mg/kg) a través de la dieta para incrementar la proporción de hembras en el cultivo. A los 25 días después de la eclosión (DDE) se observó el primordio gonadal en ejemplares con una longitud total promedio de 6.96 ± 0.92 mm, hasta el día 75 DDE (37.58 ± 6.58 mm) se observó una gónada indiferenciada evidenciada por la presencia de células germinales primordiales. La primera evidencia de diferenciación se registró a los 115 DDE (55.93 ± 14.67 mm) donde se observó la cavidad ovárica y posteriormente a los 180 DDE (115.70 ± 17.02 mm) se evidencian ovarios con ovocitos en crecimiento y testículos con espermátidas. Por lo tanto, el periodo lábil para la diferenciación sexual se encuentra entre los días 75 y 115 después de la eclosión. Por otro lado, el suministro de E2 a través de la dieta a concentraciones de 2.5, 5 y 10 mg/kg incrementó el porcentaje de hembras de 26.67% (control, no adición de E2) a un 100% en todos los tratamientos. Se encontraron diferencias en la proporción de los tipos celulares (ovogonias, ovocitos primarios en fase I y II) entre el control y los tratamientos mientras que no se registraron alteraciones histológicas como atrofia gonadal en ninguno de los casos.

Origin and differentiation of a sex chromosome system in Parodon hilarii (Pisces, Parodontidae). Satellite DNA, G- and C-banding

A satellite DNA sequence of Parodon hilarii ( named pPh2004) was isolated, cloned and sequenced. This satellite DNA is composed of 200 bp, 60% AT rich. In situ hybridization ( FISH) results revealed that the satellite DNA pPh2004 is located in the terminal regions of several chromosomes, forming highly evident blocks in some and punctual marks in others. The comparison between the FISH and C-banding results showed that the location of this satellite DNA coincides with that of most terminal heterochromatins. However, some regions are only marked by FISH whereas other regions are only marked by C-banding. The possible existence of more than one satellite DNA family could explain these partial differences. The in situ hybridization with the satellite DNA and the G- and C-bandings confirmed the presence of a sex chromosome system of the ZZ/ZW type in P. hilarii, as well as the correct identification of the Z chromosome in the karyotype. This chromosome displays a segment of terminal heterochromatin in the long arm, similar to the segment observed in the short arm of the W chromosome, also showing a G- banding pattern similar to that of the short arm and part of the long arm of the W chromosome. A hypothesis on the origin of the W chromosome from an ancestral chromosome similar to the Z chromosome is presented.

XX : XY sex chromosome system with X heterochromatinization: an early stage of sex chromosome differentiation in the Neotropic electric eel Eigenmannia virescens

An early stage of sex chromosome differentiation is reported to occur in the electric eel Eigenmannia virescens (Pisces, Sternopygidae) from populations of two tributaries of the Parana river system (Brazil). Cytogenetic studies carried out in the two populations showed that the Mogi-Guacu population is characterized by 2n = 38 chromosomes and undifferentiated sex chromosomes and the Tiete population presents 2n = 38 both for males and females and an XX:XY sex chromosome system. The X-chromosome is acrocentric, easily recognized by the presence of a conspicuous heterochromatin block in its distal portion; the Y-chromosome is probably one of the medium sized acrocentrics present in the male karyotype. BrdU induced R-bands of the two populations did not reveal any difference in the euchromatic regions of the chromosomes. AluI and HaeIII restriction enzyme digestion patterns and chromomycin A3 staining of the X-chromosome are presented. The possible role of heterochromatinization in the evolution of sex chromosomes in fish is discussed.