119 resultados para Gonadal Steroid Hormones


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Modern protocols to synchronize ovulations for timed artificial insemination and timed embryo transfer that include manipulations in the proestrus period (i.e., between luteolysis and estrus) affect fertility in cattle. Specifically, stimulating pre-ovulatory follicle growth and exposure to estrogens after CL regression increase the proportion of cows pregnant and decrease late embryo mortality. Such effects may be due to both preovulatory actions of estrogens and post-ovulatory actions of progesterone, as concentrations of the later hormone may be changed in response to manipulations conducted during proestrus. In the first portion of this paper we describe strategies used recently to manipulate the proestrus period in protocols for synchronization of ovulation, and to present evidence of their effects on fertility. Manipulations of timing and prominence of sex steroids during the proestrus and early diestrus that affect fertility may act on targets such as the endometrium. This tissue expresses receptors for both estrogens and progesterone and these hormones change endometrial function to support conceptus growth and pregnancy maintenance. However, specific cellular and molecular mechanisms through which fertility is affected via manipulations of the proestrus are poorly understood. In the second portion of this paper we describe a well-defined animal model to study changes in endometrial function induced by manipulations conducted during the proestrus. Such manipulations induced endometrial changes on sex steroid receptors expression, cell proliferation, oxidative metabolism and eicosanoid synthesis in the uterus, but not on glucose transport to uterine lumen. In summary, evidence is accumulating to support a positive role of increasing duration and estrogen availability during the proestrus on fertility to synchronization protocols. Such positive effects may be through changes in endometrial function to stimulate conceptus growth and survival.

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Maternal undernutrition affects the foetal development, promoting renal alterations and adult hypertension. The present study investigates, in adult male rats, the effect of food restriction in utero on arterial blood pressure changes (AP), and its possible association with the number of nephrons, renal function and angiotensin II (AT1R/AT2R), glucocorticoid (GR) and mineralocorticoid (MCR) receptors expression. The daily food supply to pregnant rats was measured and one group (n=5) received normal quantity of food (NF) while the other group received 50% of that (FR50) (n=5). The AP was measured weekly. At 16 weeks of life, fractionator’s method was used to estimate glomeruli number in histological slices. The renal function was estimate by creatinine and lithium clearances. Blood and urine samples were collected to biochemical determination of creatinine, sodium, potassium and lithium. At 90th and 23rd days of life, kidneys were also processed to AT1R, AT2R, GR and MCR immunolocalization and for western blotting analysis. FR50 offspring shows a significant reduction in BW (FR50: 5.67 ± 0.16 vs. 6.84 ± 0.13g in NF, P<0.001) and increased AP from 6th to 12nd week (6thwk FR50: 149.1 ± 3.4 vs. 125.1 ± 3.2mmHg in NF, P<0.001and, 12ndwk FR50: 164.4 ± 4.9 vs. 144.0 ± 3.3 mmHg in NF, P=0.02). Expression of AT1R and AT2R were significantly decreased in FR50 (AT1, 59080 ± 2709 vs. 77000 ± 3591 in NF, P=0.05; AT2, 27500 ± 95.50 vs. 67870 ± 1509 in NF, P=0.001) while the expression of GR increased in FR50 (36090 ± 781.5 vs. 4446 ± 364.5 in NF, P=0.0007). The expression of MCR did not change significantly. We also verified a pronounced decrease in fractional urinary sodium excretion in FR50 offspring (0.03 ± 0.02 vs. 0.06 ± 0.04 in NF, p=0.03). This occurred despite unchanged creatinine clearance. The study led us to suggest that fetal undernutrition, with increased fetal exposure... (Complete abstract click electronic access below)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Although there are several studies on morphogenesis in Teleostei, until now there is no research describing the role of the basement membrane in the establishment of the germinal epithelium during gonadal differentiation in Characiformes. In attempt to study these events that result in the formation of ovarian and testicular structures, gonads of Gymnocorymbus ternetzi were prepared for light microscopy. During gonadal development in G. ternetzi, all individuals first developed ovarian tissue. The undifferentiated gonad was formed by somatic cells (SC) and primordial germ cells (PGCs). After successive mitosis, the PGCs became oogonia, which entered into meiosis originating oocytes. An interstitial tissue developed. In half of the individuals, presumptive female, prefollicle cells synthesized a basement membrane around oocyte forming a follicle. Along the ventral region of the ovary, the tissue invaginated to form the ovigerous lamellae, bordered by the germinal epithelium. Stroma developed and the follicle complexes were formed. The gonadal aromatase was detected in interstitial cells in the early steps of the gonadal differentiation in both sexes. In another half of the individuals, presumptive male, there was no synthesis of basement membrane. The interstitium was invaded by numerous granulocytes. Pre-Leydig cells proliferated. Apoptotic oocytes were observed and afterward degenerated. Spermatogonia appeared near the degenerating oocytes and associated to SCs, forming testicular tubules. Germinal epithelium developed and the basement membrane was synthesized. Concomitantly, there was decrease of the gonadal aromatase and increase in the 3β-HSD enzyme expression. Thus, the testis was organized on an ovary previously developed, constituting an indirect gonochoristic differentiation.

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Sexual development prior to gonadal sex differentiation is regulated by various molecular mechanisms. In fish, a molecular sex-differentiation period has been identified in species for which sex can be ascertained prior to gonadal sex differentiation. The present study was designed to identify such a period in a species for which no genetic sex markers or monosex populations are available. Siberian sturgeons undergo a slow sex-differentiation process over several months, so gonad morphology and gene expression was tracked in fish from ages 3-27 months to identify the sex-differentiation period. The genes amh, sox9, and dmrt1 were selected as male gonad markers; cyp19a1a and foxl2a as female gonad markers; and cyp17a1 and ar as markers of steroid synthesis and steroid receptivity. Sex differentiation occurred at 8 months, and was preceded by a molecular sex-differentiation period at 3-4 months, at which time all of the genes except ar showed clear expression peaks. amh and sox9 expression seemed to be involved in male sexual development whereas dmrt1, a gene involved in testis development in metazoans, unexpectedly showed a pattern similar to those of the genes known to be involved in female gonadal sex differentiation (cyp19a1 and foxl2a). In conclusion, the timing of and gene candidates involved with molecular sex differentiation in the Siberian sturgeon were identified. Mol. Reprod. Dev. 2015. © 2015 Wiley Periodicals, Inc.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Objective: The objective of this work, and review concepts on the physiology of hormones Adrenals to enhance pre, trans and post-operative care to dentists facing surgical, dental care of immunosuppressed patients. Literature review: The corticosteroids are among the most used drugs in medicine in recent times due to its anti-inflammatory and immunosuppressive activities, especially in transplant patients and patients with chronic autoimmune diseases. However, the continuing use of these drugs leads to a decrease in endogenous production of cortisol by the adrenal. Besides depressing the patient’s immune system, it may generate many parallel undesirable effects like blocking the production of the natural hormone of adrenal cortex, or steroid called cortisol, which may be the cause of a malfunctioning of the adrenal gland, causing hypofunction or hyperfunction of the gland. Final considerations: This fact will lead to changes in the planning of dental surgery, where it will be necessary special actions towards the patients who have this condition.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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You can set the resistance training such as making a move against a resistance by performing a muscle contraction and generating a muscular adaptation. This form of training, was initially used only in training athletes aiming to strengthen and improve fitness. Some coaches did not give proper focus, as the increase in muscle mass would cause loss of flexibility and agility. But over time a huge evolution occurred within this area and the practitioners of resistance training are no longer just athletes, and reached the whole community, from young to elderly, being a physical activity that generates a large caloric expenditure and has several health benefits, improve the cardiovascular system and decreasing the amount of body fat in the body. Cortisol is a hormone secreted from a stressful stimulus to the body, secretion undergoes control of the hypothalamic-pituitary axis, which releases the hormone into the bloodstream andrenocorticotrópico, going to the adrenal cortex responsible for their release. This has catabolic function, acting in the metabolism of carbohydrates, proteins and lipids, as well as having an important effect antiflamatório. Testosterone is a steroid hormone cholesterol from being produced by the testicles in men, as in women is produced to a lesser extent in ovary and adrenal glands, has functions androgenic and anabolic. Androgen function is responsible for the development of male sexual characteristics, while on anabolic function operates in the growth of muscles and bones, influencing the development of the human body organs. Within the metabolic changes that occur in the resistance training testosterone plays an important role in protein synthesis, influencing the production of strength and / or power during exercise. The objective of this work is through a literature review to assess the effects of resistance training on the production of these hormones and the relationship between them

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Pós-graduação em Ciência e Tecnologia Animal - FEIS