935 resultados para Gonadal steroids
Resumo:
The factors that influence Leydig cell activity currently include peptides such as neuropeptide Y (NPY). In this work we investigated the ability of this compound, injected directly into the testes of adult male rats, to alter testosterone (T) release into the general circulation. At a 5μg/kg dose administered 1h prior to challenge with human chorionic gonadotropin (hCG, 1.0 U/kg, iv), NPY significantly (P<0.01) blunted the T response to this gonadotropin. The inhibitory effect of NPY was observed in animals pretreated with an antagonist to gonadotropin-releasing hormone or not, indicating that the decrease in plasma T found was most likely independent of pituitary luteinizing hormone. However, testicular levels of steroidogenic acute regulatory (STAR) protein or translocator protein (TSPO) in the Leydig cells did not exhibit consistent changes, which suggested that other mechanisms mediated the blunted T response to hCG. We therefore used autoradiography and immunohistochemistry methodologies to identify NPY receptors in the testes, and found them primarily located on blood vessels. Competition studies further identified these receptors as being Y(1), a subtype previously reported to modulate the vasoconstrictor effect of NPY. The absence of significant changes in STAR and TSPO levels, as well as the absence of Y(1) receptors on Leydig cells, suggest that NPY-induced decreases in T release is unlikely to represent a direct effect of NPY on these cells. Rather, the very high expression levels of Y(1) found in testicular vessels supports the concept that NPY may alter gonadal activity, at least in part, through local vascular impairment of gonadotropin delivery to, and/or blunted T secretion from, Leydig cells.
Resumo:
Survivors of childhood acute lymphoblastic leukemia (ALL) treated with radiotherapy are at risk for impaired fertility. Whether chemotherapy alone is also long-term gonadotoxic is unclear. We assessed gonadal function in 11 male ALL-survivors treated with the same chemotherapy regimen and compared sperm analysis to healthy men. While sex hormone levels were normal in all subjects, 5/11 survivors showed pathological sperm concentration and 4/11 a decreased total sperm count compared to WHO criteria. Compared to healthy controls, all quantitative parameters in semen analysis of survivors were decreased. This suggests that treatment with chemotherapeutic agents alone, even in moderate doses, might have a gonadotoxic effect.
Resumo:
A 55-year-old woman was referred because of diffuse pruritic erythematous lesions and an ischemic process of the third finger of her right hand. She was known to have anaemia secondary to hypermenorrhea. She presented six months before admission with a cutaneous infiltration on the left cubital cavity after a paravenous leakage of intravenous iron substitution. She then reported a progressive pruritic erythematous swelling of her left arm and lower extremities and trunk. Skin biopsy of a lesion on the right leg revealed a fibrillar, small-vessel vasculitis containing many eosinophils.Two months later she reported Raynaud symptoms in both hands, with a persistent violaceous coloration of the skin and cold sensation of her third digit of the right hand. A round 1.5 cm well-delimited swelling on the medial site of the left elbow was noted. The third digit of her right hand was cold and of violet colour. Eosinophilia (19 % of total leucocytes) was present. Doppler-duplex arterial examination of the upper extremities showed an occlusion of the cubital artery down to the palmar arcade on the right arm. Selective angiography of the right subclavian and brachial arteries showed diffuse alteration of the blood flow in the cubital artery and hand, with fine collateral circulation in the carpal region. Neither secondary causes of hypereosinophilia nor a myeloproliferative process was found. Considering the skin biopsy results and having excluded other causes of eosinophilia, we assumed the diagnosis of an eosinophilic vasculitis. Treatment with tacrolimus and high dose steroids was started, the latter tapered within 12 months and then stopped, but a dramatic flare-up of the vasculitis with Raynaud phenomenon occurred. A new immunosuppressive approach with steroids and methotrexate was then introduced. This case of aggressive eosinophilic vasculitis is difficult to classify into the usual forms of vasculitis and constitutes a therapeutic challenge given the resistance to current immunosuppressive regimens.
Resumo:
We report a case of a 64 year old woman with spontaneous hematomas. A prior history of bleeding disorder was not known up to now. The result of investigation of coagulation was an isolated prolonged aPTT that was caused by an inhibitor of factor VIII without underlying disease (idiopathic acquired hemophilia A). Therapy with steroids and cyclophosphamid resulted in partial remission.
Resumo:
Mesenchymal stromal cells (MSCs), which reside within various tissues, are utilized in the engineering of cartilage tissue. Dexamethasone (DEX)--a synthetic glucocorticoid--is almost invariably applied to potentiate the growth-factor-induced chondrogenesis of MSCs in vitro, albeit that this effect has been experimentally demonstrated only for transforming-growth-factor-beta (TGF-β)-stimulated bone-marrow-derived MSCs. Clinically, systemic glucocorticoid therapy is associated with untoward side effects (e.g., bone loss and increased susceptibility to infection). Hence, the use of these agents should be avoided or limited. We hypothesize that the influence of DEX on the chondrogenesis of MSCs depends upon their tissue origin and microenvironment [absence or presence of an extracellular matrix (ECM)], as well as upon the nature of the growth factor. We investigated its effects upon the TGF-β1- and bone-morphogenetic-protein 2 (BMP-2)-induced chondrogenesis of MSCs as a function of tissue source (bone marrow vs. synovium) and microenvironment [cell aggregates (no ECM) vs. explants (presence of a natural ECM)]. In aggregates of bone-marrow-derived MSCs, DEX enhanced TGF-β1-induced chondrogenesis by an up-regulation of cartilaginous genes, but had little influence on the BMP-2-induced response. In aggregates of synovial MSCs, DEX exerted no remarkable effect on either TGF-β1- or BMP-2-induced chondrogenesis. In synovial explants, DEX inhibited BMP-2-induced chondrogenesis almost completely, but had little impact on the TGF-β1-induced response. Our data reveal that steroids are not indispensable for the chondrogenesis of MSCs in vitro. Their influence is context dependent (tissue source of the MSCs, their microenvironment and the nature of the growth-factor). This finding has important implications for MSC based approaches to cartilage repair.
Resumo:
Bullous pemphigoid (BP) is the most common autoimmune subepidermal bullous disease typically affecting the elderly. Although different therapeutic regimens have been proposed, a review of the evidence is needed to aid clinicians in their decision making and management. Systemic therapies such as corticosteroids and adjuvants are effective in BP but are plagued with adverse effects, and potent topical steroids are an alternative treatment. This article reviews the evidence supporting different therapeutic options in the management of BP.
Resumo:
In birds, causes and consequences of variation in maternally-derived steroids in egg yolk have been the subject of intense experimentation. Many studies have quantified or manipulated testosterone ("T") and one of its immediate precursors, androstenedione ("A4") - often lumping the two steroids as "androgens" and treating them as functionally equivalent. However, yolk A4 is deposited in substantially higher concentrations than T, binds only weakly to the androgen receptor, and is readily converted into either T or estrone by steroidogenic enzymes present during embryonic development. Thus it may not be appropriate to assume that A4 has the same effect as T. In addition, A4's metabolic fate is likely to differ between females and males. The goals of this study were to examine the sex-specific uptake and metabolism of yolk A4 and consequences of elevated levels of yolk A4 on development and behavior of domestic chicks. Eggs were injected with 2mu Ci of tritiated androstenedione; radioactivity was detected in all tissues of day 7 and day 16 embryos and found in both aqueous and organics phases of day 7 yolk, with no difference between sexes. A second set of eggs was injected with 125ng of A4. A4 increased growth of morphological traits (tarsus, beak) in females, but not males. A4 males had smaller combs than controls; there was no treatment effect in females. A4 reduced tonic immobility behavior in both sexes. The results of this study illustrate the importance of distinguishing both between androgens and between sexes when investigating avian endocrine maternal effects. Copyright 2013 Elsevier Inc. All rights reserved.
Resumo:
In 2000, fishermen reported the appearance of deformed reproductive organs in whitefish (Coregonus spp.) from Lake Thun, Switzerland. Despite intensive investigations, the causes of these abnormalities remain unknown. Using gene expression profiling, we sought to identify candidate genes and physiological processes possibly associated with the observed gonadal deformations, in order to gain insights into potential causes. Using in situ-synthesized oligonucleotide arrays, we compared the expression levels at 21,492 unique transcript probes in liver and head kidney tissue of male whitefish with deformed and normally developed gonads, respectively. The fish had been collected on spawning sites of two genetically distinct whitefish forms of Lake Thun. We contrasted the gene expression profiles of 56 individuals, i.e., 14 individuals of each phenotype and of each population. Gene-by-gene analysis revealed weak expression differences between normal and deformed fish, and only one gene, ictacalcin, was found to be up-regulated in head kidney tissue of deformed fish from both whitefish forms, However, this difference could not be confirmed with quantitative real-time qPCR. Enrichment analysis on the level of physiological processes revealed (i) the involvement of immune response genes in both tissues, particularly those linked to complement activation in the liver, (ii) proteolysis in the liver and (iii) GTPase activity and Ras protein signal transduction in the head kidney. In comparison with current literature, this gene expression pattern signals a chronic autoimmune disease in the testes. Based on the recent observations that gonad deformations are induced through feeding of zooplankton from Lake Thun we hypothesize that a xenobiotic accumulated in whitefish via the plankton triggering autoimmunity as the likely cause of gonad deformations. We propose several experimental strategies to verify or reject this hypothesis.
Resumo:
Dietary supplements (DS) are easily available and increasingly used, and adverse hepatic reactions have been reported following their intake. To critically review the literature on liver injury because of DSs, delineating patterns and mechanisms of injury and to increase the awareness towards this cause of acute and chronic liver damage. Studies and case reports on liver injury specifically because of DSs published between 1990 and 2010 were searched in the PubMed and EMBASE data bases using the terms 'dietary/nutritional supplements', 'adverse hepatic reactions', 'liver injury'; 'hepatitis', 'liver failure', 'vitamin A' and 'retinoids', and reviewed for yet unidentified publications. Significant liver injury was reported after intake of Herbalife and Hydroxycut products, tea extracts from Camellia sinensis, products containing usnic acid and high contents of vitamin A, anabolic steroids and others. No uniform pattern of hepatotoxicity has been identified and severity may range from asymptomatic elevations of serum liver enzymes to hepatic failure and death. Exact estimates on how frequent adverse hepatic reactions occur as a result of DSs cannot be provided. Liver injury from DSs mimicking other liver diseases is increasingly recognized. Measures to reduce risk include tighter regulation of their production and distribution and increased awareness of users and professionals of the potential risks.
Resumo:
The availability of new topical preparations for the treatment of left sided ulcerative colitis ulcerosa offers a therapy optimization for many patients. Rectal application of steroids and 5-aminosalicylic acid (5-ASA) is associated with fewer side effects and has a higher therapeutic efficacy in mild to moderate-active left-sided colitis as compared to a systemic therapy. Often it is argued that the patients' compliance is insufficient with a rectal therapy. However, with sufficient information on the proven advantages this is usually not the case. The rectal application of drugs in distal ulcerative colitis is suitable also for the maintenance of remission. Therefore the new therapy guidelines recommend topical therapy more than in former times. Subsequently, these manuscripts focussed specifically on the topical therapy of distal colitis, to elucidate that clear treatment advantages are present in daily practice.
Resumo:
Context Steroidogenic acute regulatory protein (StAR) is crucial for transport of cholesterol to mitochondria where biosynthesis of steroids is initiated. Loss of StAR function causes lipoid congenital adrenal hyperplasia (LCAH). Objective StAR gene mutations causing partial loss of function manifest atypical and may be mistaken as familial glucocorticoid deficiency. Only a few mutations have been reported. Design To report clinical, biochemical, genetic, protein structure and functional data on two novel StAR mutations, and to compare them with published literature. Setting Collaboration between the University Children's Hospital Bern, Switzerland, and the CIBERER, Hospital Vall d'Hebron, Autonomous University, Barcelona, Spain. Patients Two subjects of a non-consanguineous Caucasian family were studied. The 46,XX phenotypic normal female was diagnosed with adrenal insufficiency at the age of 10 months, had normal pubertal development and still has no signs of hypergonodatropic hypogonadism at 32 years of age. Her 46,XY brother was born with normal male external genitalia and was diagnosed with adrenal insufficiency at 14 months. Puberty was normal and no signs of hypergonadotropic hypogonadism are present at 29 years of age. Results StAR gene analysis revealed two novel compound heterozygote mutations T44HfsX3 and G221S. T44HfsX3 is a loss-of-function StAR mutation. G221S retains partial activity (~30%) and is therefore responsible for a milder, non-classic phenotype. G221S is located in the cholesterol binding pocket and seems to alter binding/release of cholesterol. Conclusions StAR mutations located in the cholesterol binding pocket (V187M, R188C, R192C, G221D/S) seem to cause non-classic lipoid CAH. Accuracy of genotype-phenotype prediction by in vitro testing may vary with the assays employed.
Resumo:
Many metabolic hormones, growth hormone (GH), insulin-like growth factor-I (IGF-I) and insulin affect ovarian functions. However, whether ovarian steroid hormones affect metabolic hormones in cattle remains unknown. This study aimed to determine the effect of sex steroids on the plasma profiles of GH, IGF-I and insulin and their receptors in the liver and adipose tissues of dairy cows. Ovariectomized cows (n = 14) were randomly divided into four groups: control group (n = 3) was treated with saline on Day 0; oestradiol (E2) group (n = 3), with saline and 1 mg oestradiol benzoate (EB) on Day 0 and 5, respectively; progesterone (P4) group (n = 4) with two CIDRs (Pfizer Inc., Tokyo, Japan) from Day 0; and E2 + P4 group (n = 4) with two CIDRs on Day 0 that were removed on Day 6 and were immediately injected with 1 mg EB. The animals were euthanized after the experiment, and liver and adipose tissues samples were quantitatively analysed using real-time PCR for the expression of mRNA for the GH (GHR), IGF-I (IGFR-I) and insulin (IR) receptor mRNAs. Oestradiol benzoate significantly increased the number of peaks (p < 0.05), pulse amplitude (p < 0.05) and area under the curve (AUC; p < 0.01) for plasma GH; moreover, it increased plasma IGF-I concentration (p < 0.05), but it had no effect on the plasma insulin profile. P4 significantly decreased the AUC (p < 0.01), compared with the control group, whereas it did not affect the number of peaks and the amplitude of GH pulses. P4 + E2 did not affect the GH pulse profile. E2 increased the mRNA expression of GHR, IGFR-I and IR in the liver (p < 0.05), whereas both P4 and E2 + P4 did not change their expressions. Our results provide evidence that the metabolic and reproductive endocrine axes may regulate each other to ensure optimal reproductive and metabolic function.
Resumo:
Although systemic corticosteroids are successfully administered for the induction of clinical response and remission in the majority of patients with inflammatory bowel disease (IBD) presenting with a flare, a proportion of these patients demonstrate a primary nonresponse to steroids or in the case of an initial response, they develop a resistance or a steroid dependence. Long-term therapy with corticosteroids for treatment of IBD should be avoided, given the high frequency of adverse treatment effects. Knowledge about treatment strategies in case of steroid nonresponse is therefore highly relevant.
Resumo:
Bullous pemphigoid (BP) constitutes the most frequent autoimmune subepidermal blistering disease. It is associated with autoantibodies directed against the BP antigens 180 (BP180, BPAG2) and BP230 (BPAG1-e). The pathogenicity of anti-BP180 antibodies has been convincingly demonstrated in animal models. The clinical features of BP are extremely polymorphous. The diagnosis of BP critically relies on immunopathologic findings. The recent development of novel enzyme-linked immunosorbent assays has allowed the detection of circulating autoantibodies with relatively high sensitivity and specificity. Although potent topical steroids have emerged in the past decade as first-line treatment of BP, management of the disease may be challenging.
Resumo:
In Switzerland, the first course of intravenous steroids for treatment of episodes of demyelinating CNS disease is usually administered in an inpatient setting. We prospectively evaluated short term tolerance of treatment with special emphasis on sleep quality.