Rol de la osteocalcina más allá del hueso / Role of osteocalcin beyond bone

Los hallazgos osteológicos se intensi!caron en los últimos años. Se demostró que el esqueleto se comporta, además de sus funciones clásicas, como un órgano de secreción endocrina que sintetiza al menos dos hormonas: el factor de crecimiento de !broblastos 23 (FGF-23) y la osteocalcina (Ocn). La Ocn es un péptido pequeño que contiene 3 residuos de ácido glutámico. Estos residuos se carboxilan postraduccionalmente, quedando retenida en la matriz ósea. La forma decarboxilada en el primer residuo de ácido glutámico (GluOcn) fue reportada por poseer efectos biológicos; la resorción ósea es el mecanismo clave para su bioactivación. La presente revisión se centra en los conocimientos actuales sobre la función hormonal de la Ocn. A la fecha se reporta que la Ocn regularía el metabolismo energético aumentando la proliferación de células ` pancreáticas, y la secreción de insulina y de adiponectina. Sobre el músculo esquelético actuaría favoreciendo la absorción y el catabolismo de nutrientes. La función reproductiva masculina estaría regulada mediante el estímulo a las células de Leydig para sintetizar testosterona; en el desarrollo cerebral y la cognición, la Ocn aumentaría la síntesis de neurotransmisores monoaminados y disminuiría el neurotransmisor inhibidor GABA. Si bien son indispensables mayores evidencias para dilucidar los mecanismos reguladores por medio de los cuales actuaría la Ocn, los resultados enumerados en los distintos estudios experimentales establecen la importancia de este novedoso integrante molecular. Dilucidar su rol dentro de estos procesos interrelacionados en seres humanos abriría la posibilidad de utilizar a la Ocn en el tratamiento de enfermedades endocrino-metabólicas. (AU)

Osteological !ndings have intensi!ed in recent years. The skeleton behaves as an endocrine secretion organ that synthesizes at least two hormones: osteocalcin (Ocn) and !broblast growth factor 23 (FGF-23). Ocn is a small peptide that contains 3 glutamic acid residues. After translation, these residues are carboxylated to make possible its retention into the bone matrix. Decarboxylation on the !rst glutamic acid residue (GluOcn) has been reported to have biological effects. Bone resorption is the key mechanism for its bioactivation. This review focuses on current knowledge on Ocn hormonal function. It has been reported that Ocn regulates energy metabolism by increasing the proliferation of pancreatic ` cells, and the secretion of insulin and adiponectin. On the skeletal muscle, it may act by favoring the absorption and catabolism of nutrients. Male reproductive function might be regulated by stimulating Leydig cells to synthesize testosterone. Regarding brain development and cognition, Ocn would increase monoamine neurotransmitters synthesis and decrease inhibitory neurotransmitter GABA. Although more evidence is needed to elucidate the regulatory mechanisms of Ocn, different experimental studies establish the importance of this novel molecular mediator. Clarifying its role within interrelated processes in humans, might open the possibility of using Ocn in different treatments of endocrine-metabolic diseases. (AU)

Immunohistochemical study of aquaporin 1 and 2 in the reproductive tract of the bactrian camel (Camelus bactrianus) / Estudio inmunohistoquímico de acuaporina 1 y 2 en el tracto reproductivo del camello bactriano (Camelus bactrianus)

Spermatogenesis is associated with considerable fluid secretion or absorption in the male reproductive tract. Aquaporins (AQPs) are membrane protein channels that allow the rapid movement of water through epithelium. In the present study, immunohistochemistry was utilized to localize the expression of AQP 1, AQP2 in the testis and prostate of adult bactrian camel (Camelus bactrianus). Results show that AQP1 have intense reaction in rete testis, efferent ducts, vessels, seminiferous duct and in the prostate, AQP2 was found minor expression in the rete testis, vessels and prostate, which suggesting that AQP1 may have the main role in the absorption of the large amount of testicular fluid in male camel reproductive tract. Investigations of AQPs biology in camel could be relevant with technologies for assisted procreation in animal husbandry and aquaculture.

La espermatogénesis se asocia con la secreción de una cantidad considerable de líquido o absorción en el tracto reproductor masculino. Las acuaporinas (ACPs) son canales de proteínas de membrana que permiten el movimiento rápido de agua a través del epitelio. En el presente estudio, se utilizó inmunohistoquímica para localizar la expresión de ACP 1, ACP2 en el testículo y la próstata del camello bactriano adulto (Camelus bactrianus). Los resultados muestran que ACP1 tiene una reacción intensa en la rete testis, conductos eferentes, vasos, conductos seminíferos y en la próstata. La expresión ACP2, de menor importancia, se observó en la rete testis, vasos y próstata, lo que sugiere que ACP1 puede tener el papel principal en la absorción de gran cantidad de líquido testicular en el tracto reproductivo masculino del camello. Las investigaciones de la biología del ACP en camello podrían ser relevantes para las tecnologías de reproducción asistida de la ganadería y la acuicultura.

Estrogen receptors and function in the male reproductive system: [review] / Receptores e função do estrógeno no sistema reprodutor masculino: [revisão]

A substantial advance in our understanding on the estrogen signaling occurred in the last decade. Estrogens interact with two receptors, ESR1 and ESR2, also known as ERα and ERβ, respectively. ESR1 and ESR2 belong to the nuclear receptor family of transcription factors. In addition to the well established transcriptional effects, estrogens can mediate rapid signaling, triggered within seconds or minutes. These rapid effects can be mediated by ESRs or the G protein-coupled estrogen receptor GPER, also known as GPR30. The effects of estrogen on cell proliferation, differentiation and apoptosis are often mediated by growth factors. The understanding of the cross-talk between androgen, estrogen and growth factors signaling pathways is therefore essential to understand the physiopathological mechanisms of estrogen action. In this review we focused on recent discoveries about the nature of the estrogen receptors, and on the signaling and function of estrogen in the male reproductive system.

Durante a última década, ocorreu um avanço substancial no conhecimento da sinalização do estrógeno. Estrógenos interagem com dois receptores, ESR1 e ESR2, também conhecidos como ERα e ERβ, respectivamente. ESR1 e ESR2 pertencem à família de receptores nucleares, que funcionam como fatores de transcrição. Além dos bem estabelecidos efeitos transcricionais, os estrógenos medeiam a sinalização rápida, desencadeada dentro de segundos ou minutos. Esses efeitos rápidos podem ser mediados por ESRs ou pelo receptor de estrógeno acoplado à proteína G, GPER, também conhecido como GPR30. Os efeitos de estrógenos sobre a proliferação celular, diferenciação e apoptose são, muitas vezes, mediados por fatores de crescimento. Portanto, a compreensão da interação entre as vias de sinalização de andrógeno, estrógeno e fatores de crescimento é essencial para entender os mecanismos fisiopatológicos envolvidos na ação estrogênica. Nesta revisão, foram abordadas descobertas recentes sobre a estrutura dos receptores, a sinalização e a função do estrógeno no sistema reprodutor masculino.

Androgens and the male reproductive tract: an overview of classical roles and current perspectives: [review] / Androgênios e o trato reprodutor masculino: ações clássicas e perspectivas atuais: [revisão]

Androgens are steroid hormones that play key roles in the development and maintenance of male phenotype and reproductive function. These hormones also affect the function of several non-reproductive organs, such as bone and skeletal muscle. Endogenous androgens exert most of their effects by genomic mechanisms, which involve hormone binding to the androgen receptor (AR), a ligand-activated transcription factor, resulting in the modulation of gene expression. AR-induced non-genomic mechanisms have also been reported. A large number of steroidal and non-steroidal AR-ligands have been developed for therapeutic use, including the treatment of male hypogonadism (AR agonists) and prostate diseases (AR antagonists), among other pathological conditions. Here, the AR gene and protein structure, mechanism of action and AR gene homologous regulation were reviewed. The AR expression pattern, its in vivo regulation and physiological relevance in the developing and adult testis and epididymis, which are sites of sperm production and maturation, respectively, were also presented.

Os androgênios são hormônios esteroides com papel fundamental no desenvolvimento e na manutenção do fenótipo masculino e da função reprodutiva. Esses hormônios também afetam a função de diversos tecidos não reprodutivos, como, por exemplo, o ósseo e musculoesquelético. Os androgênios endógenos exercem a maioria de suas funções por mecanismo genômico, que envolve a ligação do hormônio ao receptor de androgênio (RA), um fator de transcrição ativado por ligante, o que resulta no controle da expressão gênica. Mecanismos não genômicos também têm sido associados aos efeitos induzidos pelo RA. Um grande número de ligantes do RA, esteroidais e não esteroidais, tem sido desenvolvido para o uso terapêutico, incluindo o tratamento do hipogonadismo masculino (agonistas do RA) e de doenças da próstata (antagonistas do RA), entre outras condições patológicas. Neste trabalho, foram discutidas as características estruturais básicas do RA (gene e proteína), os mecanismos de ação desse receptor, bem como aspectos relacionados à sua regulação homóloga. O padrão de expressão do RA, sua regulação in vivo e relevância fisiológica durante o desenvolvimento e a vida adulta na função do testículo e epidídimo, tecidos responsáveis pela produção e maturação de espermatozoides, respectivamente, também foram discutidos.

Estereología comparativa entre las glándulas del complejo prostático del conejo Oryctolagus cunniculus / Comparative stereology between the glands of the prostatic complex in the rabbit Oryctolagus cunniculus

El objetivo del estudio fue determinar algunos parámetros estereológicos de las glándulas que conforman el complejo prostático en el conejo y así, sentar las bases para estudios morfofuncionales. Se utilizaron 5 conejos (Oryctolagus cuniculus), machos, adultos y clínicamente sanos, mantenidos en el Bioterio de la Facultad de Medicina de la Universidad de La Frontera, Temuco, Chile. Fue disecada la región pélvica y se aisló el complejo prostático de las otras glándulas anexas. Las muestras fueron fijadas en Bouin, durante 24 horas y procesadas para su inclusión en paraplast. Se realizaron cortes seriados de 5 Jm de espesor, los cuales fueron teñidos con hematoxilina eosina, para su análisis estéreo lógico. Los resultados mostraron que el complejo prostático del conejo está formado por 4 glándulas: próstata (craneal a la glándula vesicular), propróstata (caudal a la glándula vesicular y craneal a la próstata) y dos parapróstata (inferiores y lateralmente situadas a la propróstata). El promedio de células glandulares en la próstata fue de 7,3 x 10(6)/ mm³ (D. E. 1,8 x 10(6)); en la propróstata fue de 10,33 x 10(6)/ mm³ (D. E. 2,45 x 10(6)); en la parapróstata derecha fue de 13,57 x 10(6)/ mm³ (D. E. 2,84 x 10(6)) y en la parapróstata izquierda fue de 11,91 x 10(6)/mm³ (D. E. 2,97 x 10(6)).E1 porcentaje promedio de células glandulares en la próstata fue de 14,12 por ciento (D. E. 3,01); en la propróstata fue de 13,56 por ciento (D. E. 3,13); en la parapróstata derecha fue de 18,80 por ciento (D. E. 3,04) y en la parapróstata izquierda de 18,59 por ciento (D. E. 3,43). Las glándulas del complejo prostático presentan diferencias morfológicas entre sí y, en especial, en sus aspectos estereológicos, siendo las parapróstatas las que presentaron un mayor número de células glandulares y mayor porcentaje de tejido glandular (semejante a la glándula bulbouretral), lo que podría indicar que cada una de las glándulas de este complejo cumple roles funcionales...

The aim of this study was to determine some stereological parameters of the glands of the prostatic complex in the rabbit and thereby setting the basis for future morphofunctional studies. Five rabbits (Oryctolagus cuniculus), males, adults, clinically healthy and mantained in the Biotery of the Faculty of Medicine of the Universidad de La Frontera, Temuco, Chile, were used. The pelvic region was dissected and the prostatic complex of the other glands was isolated. The samples were fixed in Bouin solution for 24 hours and processed for inclusion in paraplast. Serial cuts of 5mm which were stained with hematoxilin eosin for stereological analysis. The results showed that the prostatic complex of the rabbit was composed of four glands: prostate (cranial to vesicular gland), proprostate (caudal to vesicular gland and cranial to the prostate) and two paraprostates (inferior and lateral to the prostate). The average of the glandular cells in the prostate was 7,3 x 107 mm³ (S. D. 1,8 x 10s); in the proprostate was 10,33 x 107 mm³ (S. D. 2,45 x 10s); in the right paraprostate was 13,57 x 107 mm³ (S. D. 2,84 x 10s) and in the left paraprostate was 11,91 x 107 mm³ (S. D. 2,97 x 10s). The percentage average of the glandular cells in the prostate was 14,12 percent (S. D. 3,01); in the proprostate was 13,56 percent (S. D. 3,13); in the right paraprostate was 18,80 percent (S. D. 3,04) and in the left paraprostate was 18,59 percent (S. D. 3,43). The gland of the prostatic complex show morphological differences among themselves and in particular, its stereological aspects, with paraprostates which showed an increased number of glandular cells and higher percentage of glandular tissue ( similar to the bulbourethral gland), which could indicate that each of the glands of this complex plays specific functional roles in the reproductives processes.

Concentration of cations in different parts of male reproductive system and their influence on in vitro sperm motility in lizard, Mabuya carinata Schneider.

Concentrations of mono- and divalent cations in the testis, three different regions of the epididymis and the vas deferens of lizard, M. carinata were determined. The concentrations of Na+, K+ and Ca2+ increased gradually from testis to vas deferens. However, no significant variation in the levels of Mg2+ was observed between testis and anterior epididymis, and between posterior epididymis and vas deferens. Further, in an in vitro sperm motility study, wherein different concentrations of the cations were tested, the maximum forward progressive motility of posterior epididymal spermatozoa was observed following treatment with 140 mMNaCl, 25 mM KCl, and 50 mM CaCl2 whereas, treatment with magnesium brought about a decrease in sperm motility. The results indicate that Na+, K+, and Ca2+ have stimulatory effect at an optimum dose, whereas Mg2+ has an inhibitory effect even at very low concentration, on sperm motility in the lizard M carinata.

Male accessory gland secretory protein polymorphism in natural populations of Drosophila nasuta nasuta and Drosophila sulfurigaster neonasuta.

Male accessory gland secretory protein polymorphism was analysed in natural populations of Drosophila nasuta nasuta and D. sulfurigaster neonasuta for the first time, using SDS-PAGE to score polymorphism of these proteins in 2788 individuals of D. n. nasuta and 2232 individuals of D. s. neonasuta from 12 different populations from southern India. A total of 25 and 18 variant protein phenotypes were identified in D. n. nasuta and D. s. neonasuta, respectively. Protein fractions of group III were more polymorphic than those from groups I and II. The results show that accessory gland secretory proteins show high levels of polymorphism, irrespective of species or habitat. Moreover, we have used the variation in the accessory gland proteins to assess the extent of divergence between the species and to infer their population structure. The study suggests that though both D. n. nasuta and D. s. neonasuta belong to the same subgroup, they differ in population structure, as far as accessory gland protein polymorphism is concerned.

Identification of alpha-2u globulin in the rat preputial gland by MALDI-TOF analysis.

The low molecular mass proteins found in the pheromonal sources such as urine, saliva, glandular secretion etc have been reported as ligand carriers for the processes of chemocommunication in mammals. The preputial gland plays an important role in the production of olfactory signals for pheromonal communication. Thus, in the present study, alpha-2u globulin having molecular mass of 18 kDa has been identified in the preputial gland of Norway rat (Rattus norvegicus) by in-gel trypsin digestion and analyzing the resulting peptides by MALDI-TOF. Since preputial gland is one of the major pheromonal sources in rat, the results suggest that alpha-2u globulin might act as a carrier for hydrophobic odorants of preputial gland.

Identification of glandular (preputial and clitoral) proteins in house rat (Rattus rattus) involved in pheromonal communication.

Proteins (18-20 kDa) belonging to lipocalin family have been reported to act as carriers for ligands binding to pheromones in mouse urine, pig saliva, hamster vaginal fluid and human sweat, that are involved in pheromonal communication. As the preputial gland is a major pheromonal source, the present study was aimed to detect the specific protein bands (around 18-20 kDa) in the preputial and clitoral glands of the house rat, R. rattus. The amount of protein was higher in preputial gland of the male than that of female (clitoral) gland. A 20 kDa protein was noted in male and female glands; however, the intensity of the band was much higher in male than in female. In addition, 70, 60, 35 kDa bands, identified in male preputial gland, were absent in females. The presence of higher concentration of glandular proteins in the male preputial gland suggests that male rats may depend more on these glandular proteins for the maintenance of reproductive and dominance behaviours. The results further suggest that these glandular proteins (20 kDa) may act as a carrier for ligand binding.

Male accessory gland proteins in Drosophila: a multifaceted field [corrected].

Male accessory gland in Drosophila is a secretory tissue of the reproductive system. The proteins synthesized in the accessory gland are tissue specific, stage specific-seen only during the adult stage and sex specific in the sense of male limited expression. These secretions that form a component of the seminal fluid are transferred to the female at the time of copulation and play an important role in reproduction. In conjunction with sperm, these secretory proteins assure reproductive success by reducing the female's receptivity to mating and escalating the rate of egg laying. Some of these proteins are antibacterial in nature with a likely function of protecting the female's genital tract against microbial infection during/after mating. Most of the genes involved in the synthesis of accessory gland proteins are autosomal but a few are still X-linked. Their male specific expression is achieved at the time of sex determination. The level of expression of these genes is dose dependent and they follow Mendelian pattern of segregation. Further, majority of these proteins are rapidly evolving with high rates of non-synonymous substitutions. In this review, by considering the work carried out in different fields, we have tried to generate a comprehensive picture about the male accessory gland and the role of its proteins in the reproduction of Drosophila.

Male accessory gland secretions in hybrids of Drosophila nasuta nasuta and D. n. albomicans neither show luxuriance nor breakdown.

Male accessory gland secretions, which have a role to play in reproduction have been investigated. The number of cells that make up the gland, the quantity of secretions synthesized and the influence of these secretions on fecundity of the female have been studied in D. n. nasuta, D. n. albomicans and their F1 progeny. The results revealed that the hybrid males show a trend towards D. n. nasuta in the synthesis of male accessory gland proteins and the fecundity of the female is influenced more by its genetic constitution rather than the quantity of accessory gland secretions.

Quantitative and qualitative analysis of accessory gland secretory proteins in a few species of Drosophila immigrans group.

Quantitative and qualitative analysis of accessory gland proteins in four species of D. immigrans group has been made. Quantitative estimation of these proteins during development of the adult male revealed that there is a gradual increase in the quantity of secretions up to 7 days. The secretions constitute 72, 70, 50 and 54.2% in D.n. nasuta, D.s. neonasuta, D. rubida and D. pararubida respectively. Mating experiments showed that more than 1/3 of this stored secretory protein is transferred into the female reproductive tract during first mating. SDS-PAGE analysis of the accessory gland secretions revealed remarkable simplicity in their patterns, including the absence of age dependent alterations. In all the 4 species analysed, only the low mol. wt. fractions are not glycosylated. It was further observed that the extent of similarity between D.n. nasuta and D.s. neonasuta is greater than between D. rubida and D. pararubida.

Lipids in accessory sex glands of immature, mature and castrated male rats.

The distribution of lipids in accessory sex glands of male rats (immature, adult and castrated) has been analysed. The total lipids and phospholipids in adult rats were maximum in caput epididymis and minimal in prostate. An intermediary picture existed in the cauda epididymis and seminal vesicle. In general, phosphatidyl choline and ethanolamine were the major phospholipids in the tissues. Castration depleted the phospholipids in all the tissues. Glycerides were found to accumulate in caput and cauda epididymis, but were depleted in seminal vesicle and prostate in castrated rats. In immature rats, the total lipids were more than that of adults in caput and cauda epididymis but were less in seminal vesicle and prostate. It is suggested that these discrepancies may be due to the differences in the endogenous titres of hormones, and/or associated with structural and functional specificity of the tissues.