895 resultados para CORTICOTROPIN-RELEASING HORMONE
Resumo:
To study whether the ovarian reserve in female lymphoma patients is already reduced before the start of chemotherapy.
Resumo:
Isolated growth hormone deficiency type-2 (IGHD-2), the autosomal-dominant form of GH deficiency, is mainly caused by specific splicing mutations in the human growth hormone (hGH) gene (GH-1). These mutations, occurring in and around exon 3, cause complete exon 3 skipping and produce a dominant-negative 17.5 kD GH isoform that reduces the accumulation and secretion of wild type-GH (wt-GH). At present, patients suffering from IGHD-2 are treated with daily injections of recombinant human GH (rhGH) in order to reach normal height. However, this type of replacement therapy, although effective in terms of growth, does not prevent toxic effects of the 17.5-kD mutant on the pituitary gland, which can eventually lead to other hormonal deficiencies. Considering a well-known correlation between the clinical severity observed in IGHD-2 patients and the increased expression of the 17.5-kD isoform, therapies that specifically target this isoform may be useful in patients with GH-1 splicing defects. This chapter focuses on molecular strategies that could represent future directions for IGHD-2 treatment.
Resumo:
Endocrine and neuroendocrine cells differ from cells which rapidly release all their secreted proteins in that they store some secretory proteins in concentrated forms in secretory granules to be rapidly released when cells are stimulated. Protein aggregation is considered as the first step in the secretory granule biosynthesis and, at least in the case of prolactin and growth hormone, greatly depends on zinc ions that facilitate this process. Hence, regulation of cellular zinc transport especially that within the regulated secretory pathway is of importance to understand. Various zinc transporters of Slc30a/ZnT and Slc39a/Zip families have been reported to fulfil this role and to participate in fine tuning of zinc transport in and out of the endoplasmic reticulum, Golgi complex and secretory granules, the main cellular compartments of the regulated secretory pathway. In this review, we will focus on the role of zinc in the formation of hormone-containing secretory granules with special emphasis on conditions required for growth hormone dimerization/aggregation. In addition, we highlight the role of zinc transporters that govern the process of zinc homeostasis in the regulated hormone secretion.
Towards optimal treatment with growth hormone in short children and adolescents: evidence and theses
Resumo:
Treatment with growth hormone (GH) has become standard practice for replacement in GH-deficient children or pharmacotherapy in a variety of disorders with short stature. However, even today, the reported adult heights achieved often remain below the normal range. In addition, the treatment is expensive and may be associated with long-term risks. Thus, a discussion of the factors relevant for achieving an optimal individual outcome in terms of growth, costs, and risks is required. In the present review, the heterogenous approaches of treatment with GH are discussed, considering the parameters available for an evaluation of the short- and long-term outcomes at different stages of treatment. This discourse introduces the potential of the newly emerging prediction algorithms in comparison to other more conventional approaches for the planning and evaluation of the response to GH. In rare disorders such as those with short stature, treatment decisions cannot easily be deduced from personal experience. An interactive approach utilizing the derived experience from large cohorts for the evaluation of the individual patient and the required decision-making may facilitate the use of GH. Such an approach should also lead to avoiding unnecessary long-term treatment in unresponsive individuals.
Resumo:
Advances in novel molecular biological diagnostic methods are changing the way of diagnosis and study of metabolic disorders like growth hormone deficiency. Faster sequencing and genotyping methods require strong bioinformatics tools to make sense of the vast amount of data generated by modern laboratories. Advances in genome sequencing and computational power to analyze the whole genome sequences will guide the diagnostics of future. In this chapter, an overview of some basic bioinformatics resources that are needed to study metabolic disorders are reviewed and some examples of bioinformatics analysis of human growth hormone gene, protein and structure are provided.
Resumo:
Hormone sensitive lipase (HSL) regulates the hydrolysis of acylglycerols and cholesteryl esters (CE) in various cells and organs, including enterocytes of the small intestine. The physiological role of this enzyme in enterocytes, however, stayed elusive. In the present study we generated mice lacking HSL exclusively in the small intestine (HSLiKO) to investigate the impact of HSL deficiency on intestinal lipid metabolism and the consequences on whole body lipid homeostasis. Chow diet-fed HSLiKO mice showed unchanged plasma lipid concentrations. In addition, feeding with high fat/high cholesterol (HF/HC) diet led to unaltered triglyceride but increased plasma cholesterol concentrations and CE accumulation in the small intestine. The same effect was observed after an acute cholesterol load. Gavaging of radioactively labeled cholesterol resulted in increased abundance of radioactivity in plasma, liver and small intestine of HSLiKO mice 4h post-gavaging. However, cholesterol absorption determined by the fecal dual-isotope ratio method revealed no significant difference, suggesting that HSLiKO mice take up the same amount of cholesterol but in an accelerated manner. mRNA expression levels of genes involved in intestinal cholesterol transport and esterification were unchanged but we observed downregulation of HMG-CoA reductase and synthase and consequently less intestinal cholesterol biosynthesis. Taken together our study demonstrates that the lack of intestinal HSL leads to CE accumulation in the small intestine, accelerated cholesterol absorption and decreased cholesterol biosynthesis, indicating that HSL plays an important role in intestinal cholesterol homeostasis.
Resumo:
Parasites are linked with their host in a trophic interaction with implications for both hosts and parasites. Interaction stretches from the host's immune response to the structuring of communities and the evolution of biodiversity. As in many species sex determines life history strategy, response to parasites may be sex-specific. Males of vertebrate species tend to exhibit higher rates of parasites than females. Sex-associated hormones may influence immunocompetence and are hypothesised to lead to this bias. In a field study, we tested the prediction of male biased parasitism (MBP) in free ranging chamois (Rupicapra rupicapra rupicapra), which are infested intensely by gastrointestinal and lung helminths. We further investigated sex differences in faecal androgen (testosterone and epiandrosterone), cortisol and oestrogen metabolites using enzyme immunoassays (EIA) to evaluate the impact of these hormones on sex dependent parasite susceptibility. Non-invasive methods were used and the study was conducted throughout a year to detect seasonal patterns. Hormone levels and parasite counts varied significantly throughout the year. Male chamois had a higher output of gastrointestinal eggs and lungworm larvae when compared to females. The hypothesis of MBP originating in sex related hormone levels was confirmed for the elevated output of lungworm larvae, but not for the gastrointestinal nematodes. The faecal output of lungworm larvae was significantly correlated with androgen and cortisol metabolite levels. Our study shows that sex differences in steroid levels play an important role to explain MBP, although they alone cannot fully explain the phenomenon.
Resumo:
This study was conducted to investigate the effects of rumen-protected tryptophan (125g tryptophan per day) in heifers and dairy cows. Blood samples from dairy cows and heifers were collected for 24h in 3-h intervals on the day before tryptophan supplementation, on day 2, 5 and 7 of tryptophan supplementation, and in heifers additionally on d 14 after tryptophan supplementation was ceased. Plasma tryptophan, melatonin, serotonin, and prolactin concentrations were determined. Tryptophan plasma concentrations on d 5 were augmented at day (11:00h) and nighttime (02:00h), (P<0.05) in response to tryptophan supplementation in heifers by 119% and in dairy cows by 47%, respectively, as compared with d 0. Melatonin increased (P<0.05) in response to tryptophan supplementation in heifers, but not in cows. The effect of tryptophan supplementation on plasma tryptophan and melatonin was reversible as demonstrated in heifers on d 14 after cessation of tryptophan supplementation. Serotonin and prolactin in plasma did not respond to tryptophan supplementation. However, milk yield during morning milking increased significantly in tryptophan supplemented cows on d 1, 3 and 4 as compared to the day before tryptophan supplementation. Additional blood samples were taken during afternoon milking in cows at 1-min intervals for the analyses of oxytocin and prolactin on the day before the start and on d 7 of tryptophan supplementation. Milk flow curves were recorded during milking. No effect of tryptophan supplementation on the milking related release of oxytocin and prolactin and on any characteristic of milk flow was observed. In conclusion, tryptophan supplementation caused increased plasma tryptophan in cows and heifers and plasma melatonin in heifers. However, plasma serotonin, prolactin and oxytocin release in cows remained unchanged by tryptophan supplementation. Milk yield at morning milking increased slightly and transiently in response to tryptophan supplementation.
Resumo:
The majority of mutations that cause isolated GH deficiency type II (IGHD II) affect splicing of GH-1 transcripts and produce a dominant-negative GH isoform lacking exon 3 resulting in a 17.5-kDa isoform, which further leads to disruption of the GH secretory pathway. A clinical variability in the severity of the IGHD II phenotype depending on the GH-1 gene alteration has been reported, and in vitro and transgenic animal data suggest that the onset and severity of the phenotype relates to the proportion of 17.5-kDa produced. The removal of GH in IGHD creates a positive feedback loop driving more GH expression, which may itself increase 17.5-kDa isoform productions from alternate splice sites in the mutated GH-1 allele. In this study, we aimed to test this idea by comparing the impact of stimulated expression by glucocorticoids on the production of different GH isoforms from wild-type (wt) and mutant GH-1 genes, relying on the glucocorticoid regulatory element within intron 1 in the GH-1 gene. AtT-20 cells were transfected with wt-GH or mutated GH-1 variants (5'IVS-3 + 2-bp T->C; 5'IVS-3 + 6 bp T->C; ISEm1: IVS-3 + 28 G->A) known to cause clinical IGHD II of varying severity. Cells were stimulated with 1 and 10 mum dexamethasone (DEX) for 24 h, after which the relative amounts of GH-1 splice variants were determined by semiquantitative and quantitative (TaqMan) RT-PCR. In the absence of DEX, only around 1% wt-GH-1 transcripts were the 17.5-kDa isoform, whereas the three mutant GH-1 variants produced 29, 39, and 78% of the 17.5-kDa isoform. DEX stimulated total GH-1 gene transcription from all constructs. Notably, however, DEX increased the amount of 17.5-kDa GH isoform relative to the 22- and 20-kDa isoforms produced from the mutated GH-1 variants, but not from wt-GH-1. This DEX-induced enhancement of 17.5-kDa GH isoform production, up to 100% in the most severe case, was completely blocked by the addition of RU486. In other studies, we measured cell proliferation rates, annexin V staining, and DNA fragmentation in cells transfected with the same GH-1 constructs. The results showed that that the 5'IVS-3 + 2-bp GH-1 gene mutation had a more severe impact on those measures than the splice site mutations within 5'IVS-3 + 6 bp or ISE +28, in line with the clinical severity observed with these mutations. Our findings that the proportion of 17.5-kDa produced from mutant GH-1 alleles increases with increased drive for gene expression may help to explain the variable onset progression, and severity observed in IGHD II.
Resumo:
BACKGROUND: Tumor levels of steroid hormone receptors, a factor used to select adjuvant treatment for early-stage breast cancer, are currently determined with immunohistochemical assays. These assays have a discordance of 10%-30% with previously used extraction assays. We assessed the concordance and predictive value of hormone receptor status as determined by immunohistochemical and extraction assays on specimens from International Breast Cancer Study Group Trials VIII and IX. These trials predominantly used extraction assays and compared adjuvant chemoendocrine therapy with endocrine therapy alone among pre- and postmenopausal patients with lymph node-negative breast cancer. Trial conclusions were that combination therapy provided a benefit to pre- and postmenopausal patients with estrogen receptor (ER)-negative tumors but not to ER-positive postmenopausal patients. ER-positive premenopausal patients required further study. METHODS: Tumor specimens from 571 premenopausal and 976 postmenopausal patients on which extraction assays had determined ER and progesterone receptor (PgR) levels before randomization from October 1, 1988, through October 1, 1999, were re-evaluated with an immunohistochemical assay in a central pathology laboratory. The endpoint was disease-free survival. Hazard ratios of recurrence or death for treatment comparisons were estimated with Cox proportional hazards regression models, and discriminatory ability was evaluated with the c index. All statistical tests were two-sided. RESULTS: Concordance of hormone receptor status determined by both assays ranged from 74% (kappa = 0.48) for PgR among postmenopausal patients to 88% (kappa = 0.66) for ER in postmenopausal patients. Hazard ratio estimates were similar for the association between disease-free survival and ER status (among all patients) or PgR status (among postmenopausal patients) as determined by the two methods. However, among premenopausal patients treated with endocrine therapy alone, the discriminatory ability of PgR status as determined by immunohistochemical assay was statistically significantly better (c index = 0.60 versus 0.51; P = .003) than that determined by extraction assay, and so immunohistochemically determined PgR status could predict disease-free survival. CONCLUSIONS: Trial conclusions in which ER status (for all patients) or PgR status (for postmenopausal patients) was determined by immunohistochemical assay supported those determined by extraction assays. However, among premenopausal patients, trial conclusions drawn from PgR status differed--immunohistochemically determined PgR status could predict response to endocrine therapy, unlike that determined by the extraction assay.
Resumo:
Urinary hormone analysis is applied to detect an altered steroid hormone metabolism, an elevated production of biogenic amines and to non-invasively determine the protein hormone human beta-choriogonadotropin indicating a pregnancy. Occasionally, these determinations need to be complemented by plasma- or serum hormone analysis. Clinical data including current drug therapy and urinary creatinine as reference are required to interpret any urine analysis. Diseases to be investigated by steroid hormone analysis are excess production of a typical or atypical mineralocorticoid active steroid hormones, the hormonal activity of adrenal or ovarian tumors, acne of unknown origin, hirsutism, a PCO-, an adrenogenital or a suspected Cushing syndrome. Biogenic amines should be determined in suspected secondary or refractory arterial hypertension, in case of pheochromocytoma- or paraganglioma-associated symptoms or if a serotonin-producing tumor is suspected. In children genetically determined diseases are the primary background to perform an analysis.