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Endogenous Testosterone

Alessandro Casilli, Thomas Piper, Fábio Azamor de Oliveira, Monica Costa Padilha, Henrique Marcelo Pereira, Mario Thevis, Francisco Radler de Aquino Neto
Measuring carbon isotope ratios (CIR) of urinary analytes represents a cornerstone of doping control analysis and has been particularly optimized for the detection of the misuse of endogenous steroids. Isotope ratio mass spectrometry (IRMS) of appropriate quality however necessitates adequate purities of the investigated steroids, which requires extensive pre-analytical sample clean-up steps due to both, the natural presence of the target analytes and the high complexity of the matrix. In order to accelerate the sample preparation and increase the automation of the process, the use of multidimensional gas chromatography (MDGC) prior to IRMS experiments, was investigated...
October 14, 2016: Drug Testing and Analysis
Daniel Jardines, Francesco Botrè, Cristiana Colamonici, Davide Curcio, Gemma Procida, Xavier de la Torre
The detection of the abuse of pseudo-endogenous steroids (testosterone and/or its precursors) is currently based on the application of the steroid module of the World Antidoping Agency (WADA), Athletes' Biological Passport (ABP), implemented through ADAMS. Diagnostic metabolites are monitored for every athlete and statistically evaluated with a predictive Bayesian approach. In the case of suspicious samples, the data of the ABP are confirmed and the isotope ratio mass spectrometry (IRMS) test is activated. We have previously demonstrated that IRMS enables confirmation of the non-endogenous origin of pseudo-endogenous steroids in otherwise non-suspicious samples, after a longitudinal evaluation of the ABP, even after the inclusion of additional long term diagnostic hydroxylated metabolites, and that the delta values of the parameters obtained during the IRMS confirmation process presented a much lesser variability compared to the parameters of the ABP...
October 12, 2016: Drug Testing and Analysis
Reshmi Srinath, Rebecca F Gottesman, Sherita Hill Golden, Kathryn A Carson, Adrian Dobs
BACKGROUND AND PURPOSE: Epidemiological studies in men suggest a relationship between endogenous testosterone and ischemic vascular events. We hypothesized that low testosterone is independently associated with ischemic stroke and ischemic brain changes. METHODS: In 1558 male participants (mean [SD] age, 63.1 [5.6] years; body mass index, 28.2 [4.3] kg/m(2)) from visit 4 (1996-1998) of the ARIC study (Atherosclerosis Risk in Communities) without cardiovascular disease, stroke, and previous testosterone therapy, we measured plasma total testosterone by liquid chromatography mass spectrometry using morning samples and divided levels into tertiles (median [25th-75th percentile], 377...
October 11, 2016: Stroke; a Journal of Cerebral Circulation
M Schönfelder, H Hofmann, T Schulz, T Engl, D Kemper, B Mayr, C Rautenberg, R Oberhoffer, D Thieme
Administration of low amounts of endogenous hormones - so called micro-dosages - are supposed to represent a major challenge in doping analysis. To model such a situation, we have studied transdermal administrations of 2.4 mg/24 h testosterone patches and examined various steroid concentrations in blood, urine and saliva of 11 volunteers. Multiple samples were collected at t = 0, 3, 6, 9, 24, 48 and 72 h in four different phases, i.e. all combinations with/without physical exercise and with/without testosterone...
October 10, 2016: Drug Testing and Analysis
Yufeng Gong, Hua Tian, Yifei Dong, Xiaona Zhang, Wei Wang, Shaoguo Ru
Refuse leachate is likely an important source of androgens. However, common in vitro bioassays underestimate the potential androgenic activity of leachate, owing to non-receptor-mediated mechanisms that modify the balance of sex hormones and promote the accumulation of endogenous androgens. This study aimed to develop an in vivo assay by using multiple biomarkers related to testosterone synthesis and conversion for assessing the potential androgenic activity of refuse leachate sampled from a municipal solid waste treatment plant in Qingdao, China...
October 4, 2016: Ecotoxicology and Environmental Safety
Christoph Eisenegger, Robert Kumsta, Michael Naef, Jörg Gromoll, Markus Heinrichs
A contribution to a special issue on Hormones and Human Competition Studies in non-human animals and humans have demonstrated the important role of testosterone in competitive interactions. Here, we investigated whether endogenous testosterone levels predict the decision to compete, in a design excluding spite as a motive underlying competitiveness. In a laboratory experiment with real monetary incentives, 181 men solved arithmetic problems, first under a noncompetitive piece rate, followed by a competition incentive scheme...
October 1, 2016: Hormones and Behavior
Jeremy J Allen, Susan L Herrick, Joanne E Fortune
In cattle, primordial follicles form before birth. Fetal ovarian capacity to produce progesterone and estradiol is high before follicle formation begins and decreases around the time follicles first appear (around 90 days of gestation). However, mechanisms that regulate steroid production during this time remain unclear. We hypothesized that LH stimulates progesterone and androgen production and that FSH stimulates aromatization of androgens to estradiol. To test this, we cultured pieces from fetal bovine ovaries for 10 days without or with exogenous hormones and then measured the accumulation of steroids in the culture medium by RIA...
October 3, 2016: Journal of Molecular Endocrinology
Youqiong Wang, Lipeng Tang, Wei Yin, Jiesi Chen, Tiandong Leng, Xiaoke Zheng, Wenbo Zhu, Haipeng Zhang, Pengxin Qiu, Xiaoxiao Yang, Guangmei Yan, Haiyan Hu
Sensitive and specific biomarkers are required for the diagnosis and treatment of depression because the existing diagnostic criteria are subjective and could produce false positives or negatives. Some endogenous neuroactive steroids that have shown either antidepressant effects or concentration changes in individuals with depression could provide potential biomarkers. In this study, a simple and specific method was developed to simultaneously determine seven endogenous neuroactive steroids in biological samples: cortisone, cortisol, dehydroepiandrosterone, estradiol, progesterone, pregnenolone, and testosterone...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Diego F Cobice, Dawn E W Livingstone, C Logan Mackay, Richard J A Goodwin, Lee B Smith, Brian R Walker, Ruth Andrew
Androgens are essential for male development and reproductive function. They are transported to their site of action as blood-borne endocrine hormones but can also be produced within tissues to act in intracrine and paracrine fashions. Because of this, circulating concentrations may not accurately reflect the androgenic influence within specific tissue microenvironments. Mass spectrometry imaging permits regional analysis of small molecular species directly from tissue surfaces. However, due to poor ionization and localized ion suppression, steroid hormones are difficult to detect...
October 14, 2016: Analytical Chemistry
Ke He, Hu Qu, Hui Wang, Shun Zhang, Xin-Hong Qian, Wei Li
Metastasis-associated protein 3 (MTA3) is a subunit of the Mi-2/nucleosome remodeling and deacetylase (NuRD) protein complex, with relevant roles in the regulation of cancerous epithelial to mesenchymal transition (ETM) in an estrogen-dependent manner, recently involved in the modulation of different physiological processes. Although these findings connect MTA3 expression with hormonal signaling in various systems, little is known about whether this relationship is conserved in testis where hormonal action is intensive...
September 27, 2016: Endocrinology
Efrat Koresh, Devorah Matas, Lee Koren
Testosterone (T) is a key androgen that mediates vertebrate molecular, cellular, and behavioral processes. Its manipulation is therefore of interest to a vast number of researchers studying animal behavior and reproduction, among others. Here, the usage of silastic implants across wildlife species is reviewed, and a method to manipulate rock hyrax (Procavia capensis) testosterone levels using silastic implants is presented. Using a series of in-vitro and in-vivo experiments, the secretion patterns of silastic tubes and silastic glue were tested and were surprisingly found to be similar...
October 2016: Research in Veterinary Science
Jeremy T Hua, Kerry L Hildreth, Victoria S Pelak
Endogenous testosterone in the aging man has been scrutinized extensively in regard to its effects on performance in many cognitive domains, especially verbal fluency, visuospatial and visuoperceptual abilities, memory, and executive function. Studies of testosterone supplementation have sought to identify potential cognitive improvements in men with and without baseline cognitive impairment, and have had a wide range of results. The variability in outcomes is likely related, in part, to the lack of consensus on methods for testosterone measurement and supplementation and, in part, to the disparate measures of cognitive function used in randomized controlled studies...
September 2016: Cognitive and Behavioral Neurology: Official Journal of the Society for Behavioral and Cognitive Neurology
Marta Kiałka, Tomasz Milewicz, Sandra Mrozińska, Iwona Rogatko, Krystyna Sztefko, Renata Majewska
BACKGROUND: Despite some evidence that indicates that the evolution of PCOS is related to the activity of the endogenous opioid system, and that concentration of plasma β-endorphin levels can increase pain threshold, there are no studies which evaluate pressure pain threshold in the PCOS women population. METHODS: In 48 lean women with PCOS and 38 lean women without this disorder plasma β-endorphins and PPT were measured. RESULTS: The Beta-endorphins level was higher in the PCOS group compared to the controls (15...
September 7, 2016: Minerva Endocrinologica
Allen D Seftel
No abstract text is available yet for this article.
September 2016: Journal of Urology
Naoki Nishizawa, Yoshihiro Takatsu, Satoshi Kumano, Atsushi Kiba, Junko Ban, Shunichirou Tsutsumi, Hisanori Matsui, Shin-Ichi Matsumoto, Masashi Yamaguchi, Yukihiro Ikeda, Masami Kusaka, Tetsuya Ohtaki, Fumio Itoh, Taiji Asami
Metastin/kisspeptin is an endogenous ligand of KISS1 Receptor (KISS1R). Metastin and KISS1R are suggested to play crucial roles in regulating the secretion of gonadotropin-releasing hormone (GnRH), and continuous administration of metastin derivatives attenuated the plasma testosterone levels in male rats. Our optimization studies of metastin derivatives led to the discovery of 1 (Ac-d-Tyr-d-Trp-Asn-Thr-Phe-azaGly-Leu-Arg(Me)-Trp-NH2, TAK-683), which suppressed plasma testosterone in rats at lower doses than those of leuprolide...
October 13, 2016: Journal of Medicinal Chemistry
Timothy K O'Rourke, Matthew S Wosnitzer
Opioid-induced androgen deficiency (OPIAD) was initially recognized as a possible consequence of opioid use roughly four decades ago. Long-acting opioid use carries risks of addiction, tolerance, and systemic side effects including hypogonadotropic hypogonadism with consequent testosterone depletion leading to multiple central and peripheral effects. Hypogonadism is induced through direct inhibitory action of opioids on receptors within the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) axes as well as testosterone production within the testes...
October 2016: Current Urology Reports
Maria Claudia Gonzalez Deniselle, Philippe Liere, Antoine Pianos, Maria Meyer, Fanny Aprahamian, Annie Cambourg, Noelia P Di Giorgio, Michael Schumacher, Alejandro F De Nicola, Rachida Guennoun
The The Wobbler mouse is an animal model for human motoneuron diseases, especially amyotrophic lateral sclerosis (ALS), used in the investigation of both pathology and therapeutic treatment. ALS is a fatal neurodegenerative disease, characterized by the selective and progressive death of motoneurons, leading to progressive paralysis. Previous limited studies have reported steroidal hormone dysregulation in Wobbler mouse and in ALS patients, suggesting endocrine dysfunctions which may be involved in the pathogenesis of the disease...
August 29, 2016: Endocrinology
Christelle Doebelin, Isabelle Bertin, Séverine Schneider, Martine Schmitt, Jean-Jacques Bourguignon, Caroline Ancel, Valerie Simonneaux, Frédéric Simonin, Frédéric Bihel
A series of dipeptides were designed as potential agonists of the human KiSS1-derived peptide receptor (hGPR54). While the sequence Arg-Trp-NH2 was the most efficient in terms of affinity, we established a convergent synthetic strategy to optimize the N terminus. Using two successive Sonogashira cross-coupling reactions on a solid-supported peptide, we were able to introduce various alkynes at the N terminus to afford compounds with sub-micromolar affinities for hGPR54. However, functional assays indicated the benzoylated dipeptide Bz-Arg-Trp-NH2 as the most promising compound in terms of agonistic properties...
October 6, 2016: ChemMedChem
Po-Han Lin, Cai-Yun Jian, Jou-Chun Chou, Chien-Wei Chen, Chih-Chieh Chen, Christina Soong, Sindy Hu, Fu-Kong Lieu, Paulus S Wang, Shyi-Wu Wang
The aim of this study was to investigate the involvement of androgen, mainly testosterone, in the expression of renal senescence marker protein-30 (SMP30) in male rats. We found that the renal SMP30 expression was up-regulated by endogenous testosterone stimulation during puberty. Interestingly, androgen-deficient orchidectomized (ORX) rats exhibited lower SMP30 mRNA and protein expression in the kidney, and that was restored by testosterone propionate (TP) replacement. Abrogation of androgen receptor (AR) activity by co-treatment with flutamide abolished testosterone-induced SMP30 expression in the kidney as well as in the NRK52E cells...
2016: Scientific Reports
Isabel Ruiz-Palmero, Ana Ortiz-Rodriguez, Roberto Cosimo Melcangi, Donatella Caruso, Luis M Garcia-Segura, Gabriele M Rune, Maria-Angeles Arevalo
Testosterone produced by the foetal testis is converted by male neurons to oestradiol, which masculinizes neuronal morphology. Female neurons are known to synthesize oestradiol in absence of exogenous testosterone. However, the role of neuronal oestradiol on the differentiation of foetal female neurons is unknown. Here we show that, due to endogenous neuronal oestradiol synthesis, female hippocampal neurons have higher expression of the neuritogenic protein Neurogenin 3 and enhanced neuritogenesis than males...
2016: Scientific Reports
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