A classification of genes involved in normal and delayed male puberty / 亚洲男科学杂志(英文版)

Puberty is a pivotal biological process that completes sexual maturation to achieve full reproductive capability. It is a major transformational period of life, whose timing is strongly affected by genetic makeup of the individual, along with various internal and external factors. Although the exact mechanism for initiation of the cascade of molecular events that culminate in puberty is not yet known, the process of pubertal onset involves interaction of numerous complex signaling pathways of hypothalamo-pituitary-testicular (HPT) axis. We developed a classification of the mechanisms involved in male puberty that allowed placing many genes into physiological context. These include (i) hypothalamic development during embryogenesis, (ii) synaptogenesis where gonadotropin releasing hormone (GnRH) neurons form neuronal connections with suprahypothalamic neurons, (iii) maintenance of neuron homeostasis, (iv) regulation of synthesis and secretion of GnRH, (v) appropriate receptors/proteins on neurons governing GnRH production and release, (vi) signaling molecules activated by the receptors, (vii) the synthesis and release of GnRH, (viii) the production and release of gonadotropins, (ix) testicular development, (x) synthesis and release of steroid hormones from testes, and (xi)the action of steroid hormones in downstream effector tissues. Defects in components of this system during embryonic development, childhood/adolescence, or adulthood may disrupt/nullify puberty, leading to long-term male infertility and/or hypogonadism. This review provides a list of 598 genes involved in the development of HPT axis and classified according to this schema. Furthermore, this review identifies a subset of 75 genes for which genetic mutations are reported to delay or disrupt male puberty.

Metodología para la elaboración de la Guía de práctica clínica / Methodology for the development of the Clinical guideline for the diagnosis and treatment of precocious puberty

Resumen Introducción: La Sociedad Mexicana de Endocrinología Pediátrica presenta recomendaciones para el diagnóstico y el tratamiento de la pubertad precoz (PP), condición definida como el desarrollo de caracteres sexuales por incremento en la secreción hipofisiaria de gonadotropinas antes de los 8 años en las niñas y de los 9 años en los niños. Métodos: Se realizaron tres revisiones sistemáticas de ensayos clínicos controlados sobre intervenciones para el tratamiento de la PP, pruebas diagnósticas y estudios observacionales sobre efectos a largo plazo de la PP. La evaluación de la calidad de los estudios y la extracción de datos se realizó por pares. La evidencia se graduó con el sistema de la Scottish Intercollegiate Guidelines Network (SIGN) y del Oxford Centre for Evidence-Based Medicine (OCEBM) para las recomendaciones sobre la intervención y el diagnóstico, respectivamente. Las recomendaciones generadas se sometieron a un consenso por el método Delphi y fueron validadas por otros 143 endocrinólogos pediatras certificados mediante un cuestionario en línea. Resultados: Mediante consenso se generaron 12 recomendaciones para el diagnóstico de PP, siete sobre diagnóstico de causas secundarias de PP, ocho sobre intervenciones para inhibición de la pubertad, cinco sobre otras intervenciones en PP y 14 para la monitorización del tratamiento y el seguimiento de estos pacientes. Se obtuvo más del 90% de aprobación para cada una de las recomendaciones por el grupo de endocrinólogos certificados que respondieron el cuestionario en línea. Conclusiones: Si bien se logró un alto grado de consenso para las recomendaciones para el diagnóstico, el tratamiento y la monitorización de la PP entre los endocrinólogos pediatras, el nivel de evidencia para la mayoría de estas recomendaciones resultó bajo.

Abstract Background: The Mexican Society of Pediatric Endocrinology presents recommendations for the diagnosis and treatment of precocious puberty (PP), a condition defined as the development of sexual characteristics due to an increase in pituitary gonadotropin secretion before 8 or 9 years of age in girls and boys, respectively. Methods: Three systematic reviews were conducted: controlled clinical trials on interventions for PP treatment, diagnostic tests, and observational studies on the long-term effects of PP. The quality evaluation and data extraction from the studies were conducted by two independent reviewers. The Scottish Intercollegiate Guidelines Network and the Oxford Center for Evidence-Based Medicine systems were used for grading the quality of evidence for recommendations on intervention and diagnosis, respectively. Recommendations were submitted to a consensus by a Delphi method and were validated by another 143 certified pediatric endocrinologists through an online questionnaire. Results: The group generated 12 recommendations on the diagnosis of PP, seven on the diagnosis of secondary causes of PP, eight on interventions for inhibition of puberty, five on other interventions for PP treatment, and 14 for the monitoring and follow-up of these patients. The online questionnaires submitted to certified pediatric endocrinologists showed more than 90% of approval for each one of the recommendations. Conclusions: Although a high degree of consensus for the recommendations for diagnosis, treatment, and monitoring of PP among pediatric endocrinologists was achieved, most of these recommendations showed a low level of evidence.

Premature ovarian failure: a critical condition in the reproductive potential with various genetic causes

Premature ovarian failure [POF] is identified as a heterogeneous disorder leading to amenorrhea and ovarian failure before the age of 40 years. The first known symptom of the disease is having irregular menstrual periods. The phenotype appearance of POF depends significantly on the variations in hormones. Low levels of gonadal hormones [estrogens and inhibins] and increased level of gonadotropins [luteinizing hormone [LH] and Follicle stimulating hormone [FSH]] [hypergonadotropic amenorrhea] are well documented as causes of POF. There is an association between the failure of germ cell development and complete ovarian failure, and consistently decreased number of germ cells is more likely associated with partial ovarian failure resulting in secondary amenorrhea. A literature review on recent findings about POF and its association with genomic alterations in terms of genes and chromosomes. POF is a complex heterogeneous disorder. Some of POF cases are carriers of a single gene mutation inherited in an autosomal or X-linked manner while a number of patients suffer from a chromosome abnormality like Turner syndrome in mosaic form and manifest secondary amenorrhea associated with ovarian dysgenesis. Among many of the known involved genes in POF development, several are prove to be positively associated to the disease development in different populations. While there is a promising association between X chromosome anomalies and specific gene mutations with POF, genome-wide analysis could prove a powerful tool for identifying the most important candidate genes that influence POF manifestation

Studies on the reproductive and developmental biology of Cichlasoma dimerus (Percifomes, Cichlidae): [review]

Many characteristics of the South American teleost fish Cichlasoma dimerus (body size, easy breeding, undemanding maintenance) make it amenable to laboratory studies. In the last years, many of the fundamental aspects of its reproductive and developmental biology have been addressed in our laboratory. Rather recently, the immunohistochemical localization of pituitary hormones involved in reproduction and in background color adaptation has been described in both adult and developing individuals, and the role of FSH in ovarian differentiation has been established. These findings have been correlated with mapping of some of their brain-derived controlling hormones. The latter include brain-derived gonadotropins which were shown to be active in vitro in the control of pituitary hormone secretions. The emerging picture shows C. dimerus as an interesting species in which many of their basic features have already been investigated and which conform a solid platform for comparative studies correlating neurohormones, pituitary hormones and behavior, from the molecular to the organismic level.

Reproductive alterations in male rats exposedperinatally to Solanum lycocarpum fruits / Alterações reprodutivas em ratos machos expostos perinatalmente aos frutos da Solanum lycocarpum

This work employed pregnant rats treated with Solanum lycocarpum unripe fruits (10% in diet) from gestation day (GD) 06 to post-natalday (PND) 07, for the evaluation of the sperm number, daily sperm production and epididymal sperm transit time of the male offspring at PND 60 and PND 90. No differences were observed in the daily sperm production (DSP) and sperm number in the testis of the exposed males at PND 60 and PND 90. Also, no alterations were observed in sperm transit time in the caput epididymis of the exposed males at PND 60 and PND 90. However, a reduced sperm transit time was observed in the corpus/cauda epididymis of the experimental males at PND 90. The last data may explain the reduced sperm number observed in the corpus/cauda epididymis of the experimental male rats at PND 90. These data show that the male rats exposed to S.lycocarpum fruits during gestation did not present alterations in testis sperm production and number, however the sperm transit time through epididymis was impaired, resulting in a decreased number of spermatozoa in epididymis cauda. We conclude that S. lycocarpummay cause imbalance on hypothalamus-pituitary gland axis

Ratas prenhes foram tratadas do dia 06 da gestação (GD 06) ao dia 07 pós-natal (PND 07) com frutos verdes secos e moídos da Solanum lycocarpum (10% na ração). Após nascimento das ninhadas, foi avaliado na prole masculina adulta aos 60 e 90 dias de vida, o número de espermátides e a produção espermática diária nos testículos e o tempo de trânsito espermático no epidídimo. A exposição não foi capaz de promover alterações na produção espermática diária (DSP) e no número de espermátides produzidas pelo testículo dos ratos expostos aos frutos verdes da S. lycocarpum durante a gestação e início da lactação. Não foram observadas alterações no tempo de trânsito espermático na cabeça do epidídimo, porém, foi constatado menor número de espermatozóides no corpo/cauda do epidídimo nos machos experimentais com 90 dias de vida, provavelmente resultante do menor tempo de trânsito espermático observado no corpo/cauda do epidídimo aos PND 90. Estes dados sugerem que a exposição de ratos aos frutos verdes da S. lycocarpum durante a gestação e início dalactação, não foi suficiente para promover alterações na produção mas sim no trânsito espermático, indicando possível alteração no eixo hormônio liberador das gonadotrofinas hipotálamo-hipófise-gônada

Update on the etiology, diagnosis and therapeutic management of sexual precocity: [review]

Precocious puberty is defined as the development of secondary sexual characteristics before the age of 8 years in girls and 9 years in boys. Gonadotropin-dependent precocious puberty (GDPP) results from the premature activation of the hypothalamic-pituitary-gonadal axis and mimics the physiological pubertal development, although at an inadequate chronological age. Hormonal evaluation, mainly through basal and GnRH-stimulated LH levels shows activation of the gonadotropic axis. Gonadotropin-independent precocious puberty (GIPP) is the result of the secretion of sex steroids, independently from the activation of the gonadotropic axis. Several genetic causes, including constitutive activating mutations in the human LH-receptor gene and activating mutations in the Gs protein a-subunit gene are described as the etiology of testotoxicosis and McCune-Albright syndrome, respectively. The differential diagnosis between GDPP and GIPP has direct implications on the therapeutic option. Long-acting gonadotropin-releasing hormone (GnRH) analogs are the treatment of choice in GDPP. The treatment monitoring is carried out by clinical examination, hormonal evaluation measurements and image studies. For treatment of GIPP, drugs that act by blocking the action of sex steroids on their specific receptors (cyproterone, tamoxifen) or through their synthesis (ketoconazole, medroxyprogesterone, aromatase inhibitors) are used. In addition, variants of the normal pubertal development include isolated forms of precocious thelarche, precocious pubarche and precocious menarche. Here, we provide an update on the etiology, diagnosis and management of sexual precocity.

A puberdade precoce é definida como o desenvolvimento dos caracteres sexuais secundários antes dos 8 anos nas meninas e dos 9 anos nos meninos. A puberdade precoce dependente de gonadotrofinas (PPDG) resulta da ativação prematura do eixo hipotálamo-hipófise-gonadal e mimetiza o desenvolvimento puberal fisiológico, embora em idade cronológica inadequada. A avaliação hormonal, principalmente os valores de LH basal e após estímulo com GnRH exógeno confirmam a ativação do eixo gonadotrófico. A puberdade precoce independente de gonadotrofinas (PPIG) é o resultado da secreção de esteróides sexuais independentemente da ativação do eixo gonadotrófico. Diversas causas genéticas, incluindo mutações ativadoras constitutivas no gene do receptor do LH humano e mutações ativadoras no gene da subunidade a da proteína G representam as etiologias da testotoxicose e da síndrome de McCune Albright, respectivamente. O diagnóstico diferencial entre PPDG e PPIG tem implicação direta na opção terapêutica. Análogos de GnRH de ação prolongada é o tratamento de escolha da PPDG. A monitorização do tratamento da PPDG é realizada pelo exame clínico, avaliação hormonal e exames de imagem. Para o tratamento da PPIG, são usadas drogas que bloqueiam a ação dos esteróides sexuais nos seus receptores específicos (ciproterona, tamoxifeno) ou bloqueiam a sua síntese (cetoconazol, medroxiprogesterona e inibidores da aromatase). Variantes do desenvolvimento puberal normal incluem as formas isoladas de telarca, pubarca e menarca precoces. Nesta revisão, atualizamos a etiologia, o diagnóstico e tratamento da precocidade sexual.

Modulation of gonadotrophin release from pretreated male camel pituitary cell culture with inhibin and both calcium agonist and antagonist

The present study was conducted to identify the modification carried out by both calcium agonist [Cacl2] and antagonist [VHcI] and inhibin like material [OTLP4] on the GnRH stimulated release of FSH and LH from male camel pituitary cell culture collected during breeding and non breeding seasons. The data obtained showed that 100 and 200 ul/ ml of GnRH was able to release both FSH and LH from pituitaries collected during the year. OTLP4 as an inhibin-like preparation was able to block FSH release from the pituitary especially during non breeding season. Calcium chloride pretreatment has a pronounced effect on LH release without any effect on FSH. The higher dose of calcium chloride unable to release LH from pituitaries collected during breeding season and it may be due to the calcium desensitizing effect. VHcl has a potent effect in blocking LH release to the media by all doses used. The blocking effect on FSH was obtained only when VHcI was used in a higher dose. The use of VHcl in the field for treatment of cardiovascular diseases and its effect on male reproduction need further in vivo investigation

mRNA translation during oocyte maturation plays a key role in development of primordial germ cells in Xenopus embryos.

It is believed that cytoplasmic localization in the egg is necessary for development of primordial germ cells (PGCs) in Xenopus embryos. In this study, we sought to determine if translation of maternal mRNA during oocyte maturation is involved in the development of PGCs. Donor oocytes were collected from both stimulated (those who receive gonadotropin) and unstimulated females, artificially matured and fertilized using a host transfer technique. Using chloramphenicol (50 microM and 500 microM RNA), RNA translation was inhibited during oocyte maturation. Our results showed that in unstimulated embryos treated with 50 microM chloramphenicol, there was a significant reduction in the number of PGCs reaching genital ridges. In stimulated embryos, however, the number of PGCs was unchanged unless a higher concentration (500 microM) of chloramphenicol was used. From these results it is suggested that maternal mRNA translation during oocyte maturation plays a key role in development of PGCs.

Gonadosomatic and hepatosomatic indices of the freshwater fish Notopterus notopterus (Pallas) in response to some heavy metal exposure.

Area wise, the measurement of LC50 for pollutants is of great value in predicting the safe concentration dose of the contaminant in the environment on different aquatic species. The lethality of toxic substances including heavy metals to the aquatic organisms are usually assessed by following static bio-assay or continuous flow methods. The toxicity tests for mercuric chloride (HgCl2), cadmium chloride (CdCl2) and their mixture on Notopterus notopterus was determined by using 96h LC50 concentration on fish N. notopterus which indicated that cadmium chloride (CdCl2) was less toxic and mercuric chloride (HgCl2) was most highly toxic. The order of toxicity is mercuric chloride > mixture > cadmium chloride. On the basis of gonadosomatic index the reproductive cycle of N. notopterus can be categorised into immature, developing, maturing, mature, ripe and spent stages. Liver forms important organ of the body, which has a role in the ovarian development. On exposure to heavy metals at sublethal concentration both GSI (gonadosomatic index) and HSI (hepatosomatic index) are reduced.

Is the infertility in hypothyroidism mainly due to ovarian or pituitary functional changes?

The objective of the present study was to examine whether hypothyroidism affects the reproductive system of adult female rats by evaluating ovarian morphology, uterus weight and the changes in serum and pituitary concentrations of prolactin and gonadotropins. Three-month-old female rats were divided into three groups: control (N = 10), hypothyroid (N = 10), treated with 0.05 percent 6-propyl-2-thiouracil (PTU) in drinking water for 60 days, and T4-treated group (N = 10), receiving daily sc injections of L-thyroxine (0.8 æg/100 g body weight) during the last 10 days of the experiment. At the end of 50 days of hypothyroidism no hypothyroid animal showed a regular cycle, while 71 percent of controls as well as the T4-treated rats showed regular cycles. Corpora lutea, growing follicles and mature Graafian follicles were found in all ovaries studied. The corpora lutea were smaller in both the hypothyroid and T4-replaced rats. Graafian follicles were found in 72 percent of controls and only in 34 percent of hypothyroid and 43 percent of T4-treated animals. Serum LH, FSH, progesterone and estradiol concentrations did not differ among the three groups. Serum prolactin concentration and the pituitary content of the three hormones studied were higher in the hypothyroid animals compared to control. T4 treatment restored serum prolactin concentration to the level found in controls, but only partially normalized the pituitary content of gonadotropins and prolactin. In conclusion, the morphological changes caused by hypothyroidism can be a consequence of higher prolactin production that can block the secretion and action of gonadotropins, being the main cause of the changes observed

Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro

We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 µM and 10 µM). The effect of R-PIA (10 nM) was blocked by the addition of 8-cyclopentyltheophylline (CPT), a selective A1 adenosine receptor antagonist, at the dose of 1 µM. The addition of an A2 receptor-specific agonist, 5-N-methylcarboxamidoadenosine (MECA), at the doses of 1 nM to 1 µM had no significant effect on LH or FSH secretion, suggesting the absence of this receptor subtype in the gonadotrope. However, a sharp inhibition of the basal secretion of these gonadotropins was observed after the administration of 10 µM MECA. This effect mimicked the inhibition induced by R-PIA, supporting the hypothesis of the presence of A1 receptors in the gonadotrope. R-PIA (1 nM to 1 µM) also inhibited the secretion of LH and FSH induced by phospholipase C (0.5 IU/ml) in a dose-dependent manner. These results suggest the presence of A1 receptors and the absence of A2 receptors in the gonadotrope. It is possible that the inhibition of LH and FSH secretion resulting from the activation of A1 receptors may have occurred independently of the increase in membrane phosphoinositide synthesis

Controle da secreçäo de gonodotrofinas e prolactina pelo neuropeptídio Y e sistema adrenérgico-alfa em ratas / Control of gonadotrophin and prolactin release by neuropeptide y and adrenergic-alpha sistem in rats

Este trabalho teve como objetivo investigar a participação do neuropeptídio Y e sua interação com o sistema adrenérgio-alfa na área pré-óptica medial e hipotálamo médio basal no controle da secreção de gonadotrofinas e prolactina. Para tanto, utilizou fêmeas castradas, tratadas com estrógeno e tratadas com estrógeno e progesterona em dois tipos de esquema hormonal substitutivo, um deles, o de indução de pico do hormônio luteinizante. No primeiro conjunto de experimentos, duas semanas após a ovariectomia um cânula de demora foi implantada na área pré-óptica medial e uma semana depois, um cateter foi implantado na veia jugular. No dia seguinte foram feitas microinjeçöes de bloqueadores adrenérgicos-alfa ou salina (tempo-10) e salina ou agonista para receptores do tipo Y1 (tempo 0) na área pré-óptica medial. As coletas de sangue foram feitas...

Consideraciones etiológicas y fisiopatológicas en el síndrome del ovario poliquístico y los mecanismos de anovulación / Etiologic and physiopathology considerations in the policystic ovary syndrome and anovulation mechanism

El síndrome del ovario poliquístico es una entidad que ha causado gran interés por su frecuencia, por la controversia acerca de su origen y por las repercusiones que conlleva. El estado de anovulación crónico es la vía a través de la cual se originan las alteraciones morfológicas y endocrinas del síndrome, produciendo un complejo sintomático muy variable. Dentro de las alteraciones hormonales más importantes están un hiperandrogenismo y un estado estrogénico aumentado y no antagonizado. Nuestro intés estriba en revisar los factores etiológicos y fisicopatológicos de este síndrome, así como los mecanismos de anovulación implicados

Endocrinología en las grandes alturas / Endocrinology at high altitude

El vivir en las grandes alturas, significa someterse a un medio donde predomina una baja presión de oxígeno. Ante tal situación el organismo responde en diversas formas para obtener una adaptación a este medio hipóxico. Estas respuestas pueden ser diferentes de acuerdo a la magnitud de la hipoxia. El estudio de la fisiología de altura, realizado por destacados científicos peruanos se ha constituido en uno de los más importantes campos de investigación en nuestro país en los últimos cincuenta años. En la presente revisión se ha tratado de resumir los trabajos sobre endocrinología en el nativo de la altura, que han realizado diversos investigadores del país y del extranjero, y se ha tratado de explicar en lo posible, las diferencias observadas con respecto a la endocrinología del nativo del nivel del mar. Los resultados demuestran diferencias endocrinas en el nativo de la altura, que están relacionados principalmente en el metabolismo intermedio, y en la reproducción

Hiperandrogenismo no climaterio: aspectos clinicos e laboratoriais / Hyperandrogenism in climateric women: clinical and laboratorial aspects

Foram estudadas 39 mulheres climatericas e pos-menopausais portadoras de hiperandrogenismo, das quais 27 eram pos-menopausais e 12 ainda menstruavam, na Clinica Ginecologica do Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, com o objetivo de avaliar os aspectos clinicos e laboratoriais no sentido de estabelecer o diagnostico etiologico. Os seguintes parametros foram avaliados: distribuicao etaria; queixas; tempo de menopausa; padrao mentrual nas pacientes com menstruacoes; exame fisico; avaliacao dos sintomas climatericos; peso corporeo; pressao arterial; dosagens hormonais e bioquimicas; estudo morfologico dos orgaos genitais, e o diagnostico etiologico...

Amenorreia hipergonadotropica / Hipergonadotropic amenorrehoa

No Setor de Ginecologia Endocrina e Climaterio do Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo foram estudadas 353 mulheres portadoras de amenorreia hipergonadotropica com o objetivo de analisar, retrospectivamente, os niveis alterados de gonadotropinas, e, tentar estabelecer correlacao entre possiveis padroes gonadotropicos e a etiopatogenia da amenorreia...