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Endogenous Testosterone

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https://www.readbyqxmd.com/read/28918287/steroid-hormones-and-persistent-organic-pollutants-in-plasma-from-north-eastern-atlantic-pilot-whales
#1
Katrin S Hoydal, Bjarne Styrishave, Tomasz M Ciesielski, Robert J Letcher, Maria Dam, Bjørn M Jenssen
Persistent organic pollutants (POPs) are known to have endocrine disruptive effects, interfering with endogenous steroid hormones. The present study examined nine steroid hormones and their relationships with the concentrations of selected POPs in pilot whales (Globicephala melas) from the Faroe Islands, NE Atlantic. The different steroids were detected in 15 to all of the 26 individuals. High concentrations of progesterone (83.3-211.7pmol/g) and pregnenolone (PRE; 4.68-5.69pmol/g) were found in three adult females indicating that they were pregnant or ovulating...
September 14, 2017: Environmental Research
https://www.readbyqxmd.com/read/28914204/a-review-on-the-effects-of-testosterone-supplementation-in-hypogonadal-men-with-cognitive-impairment
#2
Mohamad Nur Vaizura, Soelaiman Ima-Nirwana, Kok-Yong Chin
Cognitive function and testosterone level of men decline concurrently with aging. Low testosterone levels are associated with higher risk of Alzheimer's disease and mild cognitive impairment in men. There are continuous debates on whether this relationship is casual or causal. This paper aims to summarize the current evidence on the association between testosterone level and cognitive function in elderly men. The presence of testosterone, androgen receptor and its responsive genes hint that testosterone has biological functions in the central nervous system...
September 13, 2017: Current Drug Targets
https://www.readbyqxmd.com/read/28912255/sex-hormones-and-the-development-of-sexual-size-dimorphism-dihydrotestosterone-inhibits-growth-in-a-female-larger-lizard-sceloporus-undulatus
#3
Nicholas B Pollock, Stephanie Feigin, Marko Drazenovic, Henry B John-Alder
Sexual differences in adult body size (sexual size dimorphism; SSD) and color (sexual dichromatism) are widespread, and both male- and female-biased dimorphisms are observed even among closely related species. A growing body of evidence indicates testosterone (T) can regulate growth, thus the development of SSD, and sexual dichromatism. However, the mechanism(s) underlying these effects are conjectural, including possible conversions of T to estradiol (E2) or 5 α-dihydrotestosterone (DHT). In the present study, we hypothesized that effects of T are physiological responses mediated by androgen receptors, and we tested two specific predictions: 1) that DHT would mimic effects of T by inhibiting growth and enhancing coloration, and 2) that removal of endogenous T via surgical castration would stimulate growth...
September 14, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28911778/applications-of-isotope-ratio-mass-spectrometry-in-sports-drug-testing-accounting-for-isotope-fractionation-in-analysis-of-biological-samples
#4
Thomas Piper, Mario Thevis
The misuse of anabolic-androgenic steroids (AAS) in sports aiming at enhancing athletic performance has been a challenging matter for doping control laboratories for decades. While the presence of a xenobiotic AAS or its metabolite(s) in human urine immediately represents an antidoping rule violation, the detection of the misuse of endogenous steroids such as testosterone necessitates comparably complex procedures. Concentration thresholds and diagnostic analyte ratios computed from urinary steroid concentrations of, e...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28911175/hyperandrogenemia-induced-by-letrozole-treatment-of-pubertal-female-mice-results-in-hyperinsulinemia-prior-to-weight-gain-and-insulin-resistance
#5
Danalea V Skarra, Angelina Hernández-Carretero, Alissa J Rivera, Arya R Anvar, Varykina G Thackray
Women with polycystic ovary syndrome (PCOS) diagnosed with hyperandrogenism and ovulatory dysfunction have an increased risk of developing metabolic disorders, including type 2 diabetes and cardiovascular disease. We previously developed a model that uses letrozole to elevate endogenous testosterone levels in female mice. This model has hallmarks of PCOS, including hyperandrogenism, anovulation, and polycystic ovaries, as well as increased abdominal adiposity and glucose intolerance. In the current study, we further characterized the metabolic dysfunction that occurs after letrozole treatment to determine whether this model represents a PCOS-like metabolic phenotype...
September 1, 2017: Endocrinology
https://www.readbyqxmd.com/read/28905534/larger-testicular-volume-is-independently-associated-with-favorable-indices-of-lung-function
#6
Tae Beom Kim, I Nae Park
BACKGROUND: Men with chronic obstructive pulmonary disease, have reduced endogenous testosterone levels, but the relationship between pulmonary function and endogenous testosterone levels, is inconsistent. Testicular volume is a known indicator of endogenous testosterone levels, male fertility, and male potency. In the present study, the authors investigated the relationship, between testicular volume and lung function. METHODS: One hundred and eighty-one South Korean men age 40-70, hospitalized for urological surgery, were retrospectively enrolled, irrespective of the presence of respiratory disease...
September 1, 2017: Tuberculosis and Respiratory Diseases
https://www.readbyqxmd.com/read/28904297/sex-differences-in-the-excretion-levels-of-traditional-and-novel-urinary-biomarkers-of-nephrotoxicity-in-rats
#7
Satoshi Tsuji, Masayuki Sugiura, Shunsuke Tsutsumi, Hisaharu Yamada
Urinary biomarkers have been used widely in preclinical toxicity studies to detect dysfunctions and injuries of the kidney caused by drugs under development. While they have been well studied for evaluating nephrotoxicity, knowledge of sex differences in excretion levels of urinary biomarkers remains inadequate. We conducted experiments focused on effects of endogenous sex hormones on urinary biomarkers using intact and castrated male and female rats. Comparisons of the urinary biomarker excretion levels between intact male and female rats at 5, 7, 9 and 12 weeks of age revealed higher excretion levels of leucine aminopeptidase (LAP), γ-glutamyl transpeptidase (γGTP), total protein, liver-type fatty acid-binding protein (L-FABP), cystatin C (Cys-C) and β2-microglobulin (β2-MG), and lower excretion level of kidney injury molecule 1 (Kim-1), in male rats as compared to female rats...
2017: Journal of Toxicological Sciences
https://www.readbyqxmd.com/read/28901724/codeine-influences-the-serum-and-urinary-profile-of-endogenous-androgens-but-does-not-interact-with-the-excretion-rate-of-administered-testosterone
#8
M Lehtihet, A Andersson, A Börjesson, J Schulze, A Rane, M Ericsson, L Ekström
Today's doping tests involve longitudinal monitoring of urinary steroids including the testosterone glucuronide and epitestosterone glucuronide ratio (T/E) in an athlete biological passport (ABP). The aim of this study was to investigate the possible influence of short term use of codeine on the urinary excretion of androgen metabolites included in the steroidal module of the passport prior to and after the co-administration with testosterone. The study was designed as an open study with the subjects being their own control...
September 13, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28886024/clomiphene-citrate-effect-in-obese-men-with-low-serum-testosterone-treated-with-metformin-due-to-dysmetabolic-disorders-a-randomized-double-blind-placebo-controlled-study
#9
Carla Pelusi, Vito Angelo Giagulli, Margherita Baccini, Flaminia Fanelli, Marco Mezzullo, Alessia Fazzini, Nicola Bianchi, Matteo Domenico Carbone, Giovanni De Pergola, Marianna Mastroroberto, Antonio Maria Morselli Labate, Renato Pasquali
CONTEXT: Low testosterone (T) levels are often found in obese men with impaired glucose tolerance (IGT) and overt type 2 diabetes (T2DM); however, the mechanisms underlying this condition and its correct therapy are still under debate. OBJECTIVE: To evaluate the effectiveness of clomiphene citrate (CC) in increasing endogenous T levels in obese men with low serum T and with IGT or T2DM treated with metformin (MET). DESIGN: Cross-over, randomized, double-blind, placebo-controlled study...
2017: PloS One
https://www.readbyqxmd.com/read/28863017/debate-position-cognition-and-mood-are-not-improved-in-men-administered-exogenous-testosterone-therapy
#10
Swaytha Yalamanchi, Adrian Dobs
PURPOSE OF REVIEW: The purpose of this article is to provide an overview of the increasing evidence suggesting that exogenous testosterone therapy is not associated with improvements in cognition or mood. This article is part of a series, in this issue, in which authors are assigned opinion pieces on controversial topics pertaining to testosterone replacement. RECENT FINDINGS: Testosterone is increasingly being prescribed. Particularly in the setting of recent data suggestive of possible cardiovascular risk associated with its use; a clear understanding of the domains of health that improve with exogenous testosterone use is important...
August 24, 2017: Current Opinion in Urology
https://www.readbyqxmd.com/read/28833805/carbon-isotope-ratios-of-endogenous-steroids-in-belgian-blue-and-holstein-cattle-method-development-reference-population-studies-and-application-to-steroid-misuse-control
#11
Thomas Piper, Marlen Putz, Phillipe Delahaut, Mario Thevis
RATIONALE: The misuse of growth promoters in livestock and breeding animals is prohibited according to the laws of the European Union. Among these growth promoters, the detection of endogenous steroids like testosterone, estradiol or progesterone remains especially challenging as concentration-based urinary thresholds may not provide conclusive results due to large inter-individual variations. In addition to the detection of intact steroid esters in blood or hair, carbon isotope ratio (CIR) determinations of urinary steroids has commonly been the method of choice...
August 22, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28830317/growth-hormone-secretagogue-treatment-in-hypogonadal-men-raises-serum-insulin-like-growth-factor-1-levels
#12
John T Sigalos, Alexander W Pastuszak, Andrew Allison, Samuel J Ohlander, Amin Herati, Mark C Lindgren, Larry I Lipshultz
Realizing the reported misuse of human growth hormone (GH), investigation of a safe alternative mechanism for increasing endogenous GH is needed. Several GH secretagogues are available, including GH-releasing peptides (GHRPs) GHRP-2 and GHRP-6, and the GH-releasing hormone analog, sermorelin (SERM). Insulin-like growth factor 1 (IGF-1) serves as a surrogate marker for GH. Here, the effect of GHRP/SERM therapy on IGF-1 levels is evaluated. A retrospective review of medical records was performed for 105 men on testosterone (T) therapy seeking increases in lean body mass and fat loss who were prescribed 100 mcg of GHRP-6, GHRP-2, and SERM three times daily...
August 1, 2017: American Journal of Men's Health
https://www.readbyqxmd.com/read/28811197/seasonal-changes-in-plasma-testosterone-and-cortisol-suggest-an-androgen-mediated-regulation-of-the-pituitary-adrenal-axis-in-the-tarabul-s-gerbil-gerbillus-tarabuli-thomas-1902
#13
Yamina Zatra, Naouel Aknoun-Sail, Arezki Kheddache, Abdelouafi Benmouloud, Salima Charallah, Elara N Moudilou, Jean-Marie Exbrayat, Farida Khammar, Zaina Amirat
In the desert gerbil Gerbillus tarabuli (Thomas, 1902), cortisol is the main glucocorticosteroid produced by the adrenal glands. Plasma cortisol concentrations show highest values when testosterone is reduced and lowest values during the breeding season which occurs from early winter to late spring. In order to specify the implication of testicular androgens in these corticosteroid seasonal variations we investigated the effects induced by gonadectomy performed during the breeding season on the pituitary adrenal axis...
August 12, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28803647/determination-of-selected-endogenous-anabolic-androgenic-steroids-and-ratios-in-urine-by-ultra-high-performance-liquid-chromatography-tandem-mass-spectrometry-and-isotope-pattern-deconvolution
#14
J Pitarch-Motellón, J V Sancho, M Ibáñez, O Pozo, A F Roig-Navarro
An isotope dilution mass spectrometry (IDMS) method for the determination of selected endogenous anabolic androgenic steroids (EAAS) in urine by UHPLC-MS/MS has been developed using the isotope pattern deconvolution (IPD) mathematical tool. The method has been successfully validated for testosterone, epitestosterone, androsterone and etiocholanolone, employing their respective deuterated analogs using two certified reference materials (CRM). Accuracy was evaluated as recovery of the certified values and ranged from 75% to 108%...
August 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28802821/association-of-sex-hormones-with-metabolic-syndrome-among-egyptian-males
#15
Iman Z Ahmed, Maram M Mahdy, Hussein El Oraby
BACKGROUND: Studies have shown that testosterone and estradiol (E2) are associated with metabolic syndrome (MetS). To our knowledge, few studies, if any about the association of endogenous sex hormones with MetS have been done in Egypt. AIM: To study the relation between endogenous sex hormones and MetS among Egyptian males. SUBJECTS AND METHOD: For the study, 80 Egyptian males were enrolled: 40 males with MetS and 40 healthy age-matched males...
August 5, 2017: Diabetes & Metabolic Syndrome
https://www.readbyqxmd.com/read/28789926/commentary-on-redirecting-abiraterone-metabolism-to-fine-tune-prostate-cancer-anti-androgen-therapy-li-z-alyamani-m-li-j-rogacki-k-abazeed-m-upadhyay-sk-balk-sp-taplin-me-auchus-rj-sharifi-n-nature-2016-may-25-533-7604-547-51
#16
Byron H Lee
Abiraterone blocks androgen synthesis and prolongs survival in patients with castration-resistant prostate cancer, which is otherwise driven by intratumoral androgen synthesis. Abiraterone is metabolized in patients to Δ(4)-abiraterone (D4A), which has even greater antitumour activity and is structurally similar to endogenous steroidal 5α-reductase substrates, such as testosterone. Here, we show that D4A is converted to at least three 5α-reduced and three 5β-reduced metabolites in human serum. The initial 5α-reduced metabolite, 3-keto-5α-abiraterone, is present at higher concentrations than D4A in patients with prostate cancer taking abiraterone, and is an androgen receptor agonist, which promotes prostate cancer progression...
September 2017: Urologic Oncology
https://www.readbyqxmd.com/read/28775186/are-thyroid-nodules-associated-with-sex-related-hormones-a-cross-sectional-spect-china-study
#17
Yi Chen, Yingchao Chen, Ningjian Wang, Chi Chen, Xiaomin Nie, Qin Li, Bing Han, Fangzhen Xia, Hualing Zhai, Boren Jiang, Zhoujun Shen, Yingli Lu
OBJECTIVE: Little is known about the association between thyroid nodules (TNs) and endogenous sex hormones. We aimed to investigate the relationship between TNs and sex-related hormones among men in China. SETTING: The data were obtained from a cross-sectional study Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China study, 2014-2015) based on the population. PARTICIPANTS: In total, 4024 men over 18 years of age who were not using hormone replacement therapy and who underwent complete assays of the serum total testosterone (T), oestradiol (E2), follicle-stimulating hormone (FSH), luteinising hormone (LH) and sex hormone-binding globulin (SHBG) levels as well as thyroid ultrasonography (US) enrolled in this study...
August 3, 2017: BMJ Open
https://www.readbyqxmd.com/read/28765074/estrogenic-effects-associated-with-bisphenol-a-exposure-in-male-zebrafish-danio-rerio-is-associated-with-changes-of-endogenous-17%C3%AE-estradiol-and-gene-specific-dna-methylation-levels
#18
Fei Zhao, Penghao Wei, Jun Wang, Miao Yu, Xiaona Zhang, Hua Tian, Wei Wang, Shaoguo Ru
The binding affinity of bisphenol A (BPA) to estrogen receptors (ERs) is much lower than that of 17β-estradiol (E2), and whether there are other molecular mechanisms responsible for the estrogenic action of BPA in vivo currently remains unknown. The objective of this study was to explore the potential association between the estrogenic effect induced by bisphenol A in vivo and changes of endogenous E2 and gene specific DNA methylation levels. After a waterborne exposure of male zebrafish to 500, 1000, or 1500μg/L of BPA for 21d, vitellogenin (VTG) concentration in whole body homogenate, plasma E2 and testosterone levels, hepatic ERs mRNA expressions, gonadal cyp19a1a and cyp17a1 mRNA expressions, and methylation levels of hepatic esr1 and gonadal cyp19a1a's promoters were determined...
October 1, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28763621/age-related-testosterone-declines-can-be-detected-in-men-s-fingernails
#19
Devorah Matas, Lee Koren
Testosterone plays multiple roles in the regulation of development, physiology, reproduction, and behavior. Age-related testosterone declines are expected in the population. However, measuring circulating testosterone is especially challenging since concentrations are labile, responding to social situations and challenges. Matrices that integrate long-term testosterone levels are therefore valuable as biomarkers of mean, as well as chronic exposures. Here we report on a simple method to extract and measure accumulated testosterone from human fingernails using commercial EIA kits...
August 1, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28757249/seasonal-and-sex-differences-in-cell-proliferation-neurogenesis-and-cell-death-within-the-dentate-gyrus-of-adult-wild-caught-meadow-voles
#20
Mark D Spritzer, Alyssa W Panning, Shannon M Engelman, W Tyler Prince, Alexander E Casler, Joanna E Georgakas, Eliza C B Jaeger, Laura R Nelson, Ethan A Roy, Benjamin A Wagner
Past research indicates that female meadow voles (Microtus pennsylvanicus) show decreased neurogenesis within the hippocampus during the breeding season relative to the non-breeding season, whereas male voles show no such seasonal changes. We expanded upon these results by quantifying a variety of endogenous cell proliferation and neurogenesis markers in wild-caught voles. Adult male and female voles were captured in the summer (breeding season) or fall (non-breeding season), and blood samples and brain tissue were collected...
July 28, 2017: Neuroscience
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