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Endogenous Testosterone

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https://www.readbyqxmd.com/read/28314523/detection-of-anabolic-and-androgenic-steroids-and-or-their-esters-in-horse-hair-using-ultra-high-performance-liquid-chromatography-high-resolution-mass-spectrometry
#1
Karen Y Kwok, Timmy L S Choi, Wai Him Kwok, Jenny K Y Wong, Terence S M Wan
Anabolic and androgenic steroids (AASs) are a class of prohibited substances banned in horseracing at all times. The common approach for controlling the misuse of AASs in equine sports is by detecting the presence of AASs and/or their metabolites in urine and blood samples using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). This approach, however, often falls short as the duration of effect for many AASs are longer than their detection time in both urine and blood...
March 6, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28263535/exposure-of-rats-to-exogenous-endocrine-disruptors-17alpha-ethinylestradiol-and-benzo-a-pyrene-and-an-estrogenic-hormone-estradiol-induces-expression-of-cytochromes-p450-involved-in-their-metabolism
#2
Lucie Borek-Dohalska, Zuzana Klusonova, Jana Holecova, Marketa Martinkova, Frantisek Barta, Helena Dracinska, Tomas Cajthaml, Marie Stiborova
OBJECTIVES: The term "endocrine disruptor" (ED) is used for compounds that mimic or antagonize the effects of endogenous hormones. Synthetic estrogen 17α-ethinylestradiol (EE2) and a human carcinogen benzo[a]pyrene (BaP) are assigned as exogenous endocrine disruptors and an estrogenic hormone estradiol is a natural endogenous disruptor. Here, the potency of these three disruptors administered to rats individually and in combination to induce expression of cytochrome P450 (CYP) enzymes involved in their own metabolism (CYP1A1, 2C and 3A) in vivo was investigated...
December 18, 2016: Neuro Endocrinology Letters
https://www.readbyqxmd.com/read/28258581/effects-of-anabolic-androgenic-steroids-on-the-reproductive-system-of-athletes-and-recreational-users-a-systematic-review-and-meta-analysis
#3
REVIEW
Maria A Christou, Panagiota A Christou, Georgios Markozannes, Agathocles Tsatsoulis, George Mastorakos, Stelios Tigas
BACKGROUND: Anabolic androgenic steroids (AAS) are testosterone derivatives used by athletes and recreational users to improve athletic performance and/or enhance appearance. Anabolic androgenic steroids use may have serious and potentially irreversible adverse effects on different organs and systems, including the reproductive system. OBJECTIVE: This systematic review and meta-analysis aimed to critically assess the impact of AAS use on the reproductive system of athletes and recreational users...
March 4, 2017: Sports Medicine
https://www.readbyqxmd.com/read/28257955/sex-hormones-reduce-nnk-detoxification-through-inhibition-of-short-chain-dehydrogenases-reductases-and-aldo-keto-reductases-in-vitro
#4
Claudia Stapelfeld, Edmund Maser
Carbonyl reduction is an important metabolic pathway for endogenous and xenobiotic substances. The tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, nicotine-derived nitrosamine ketone) is classified as carcinogenic to humans (IARC, Group 1) and considered to play the most important role in tobacco-related lung carcinogenesis. Detoxification of NNK through carbonyl reduction is catalyzed by members of the AKR- and the SDR-superfamilies which include AKR1B10, AKR1C1, AKR1C2, AKR1C4, 11β-HSD1 and CBR1...
February 28, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28244681/nandrolone-decanoate-interferes-with-testosterone-biosynthesis-altering-blood-testis-barrier-components
#5
Rosario Barone, Alessandro Pitruzzella, Antonella Marino Gammazza, Francesca Rappa, Monica Salerno, Fulvio Barone, Claudia Sangiorgi, Daniela D'Amico, Nicola Locorotondo, Francesca Di Gaudio, Luigi Cipolloni, Valentina Di Felice, Stefania Schiavone, Venerando Rapisarda, Gabriele Sani, Amos Tambo, Francesco Cappello, Emanuela Turillazzi, Cristoforo Pomara
The aim of this study was to investigate whether nandrolone decanoate (ND) use affects testosterone production and testicular morphology in a model of trained and sedentary mice. A group of mice underwent endurance training while another set led a sedentary lifestyle and were freely mobile within cages. All experimental groups were treated with either ND or peanut oil at different doses for 6 weeks. Testosterone serum levels were measured via liquid chromatography-mass spectrometry. Western blot analysis and quantitative real-time PCR were utilized to determine gene and protein expression levels of the primary enzymes implicated in testosterone biosynthesis and gene expression levels of the blood-testis barrier (BTB) components...
February 28, 2017: Journal of Cellular and Molecular Medicine
https://www.readbyqxmd.com/read/28238727/testosterone-metabolism-of-equine-single-cyps-of-the-3a-subfamily-compared-to-the-human-cyp3a4
#6
S Vimercati, M Büchi, J Zielinski, N Peduto, M Mevissen
Cytochrome P450 enzymes (CYPs) are responsible for the phase I metabolism of drugs, xenobiotics and endogenous substances. Knowledge of single CYPs and their substrates is important for drug metabolism, helps to predict adverse effects and may prevent reduced drug efficacy in polypharmacy. In this study, three equine isoenzymes of the 3A subfamily, the equine flavoprotein NADPH-P450 oxidoreductase (POR), and the cytochrome b5 (CYB5) were cloned, sequenced and heterologously expressed in a baculovirus expression system...
February 24, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28223343/associations-of-steroid-sex-hormones-and-sex-hormone-binding-globulin-with-the-risk-of-type-2-diabetes-in-women-a-population-based-cohort-study-and-meta-analysis
#7
Taulant Muka, Jana Nano, Loes Jaspers, Cindy Meun, Wichor M Bramer, Albert Hofman, Abbas Dehghan, Maryam Kavousi, Joop S E Laven, Oscar H Franco
It remains unclear whether endogenous sex hormones (ESH) are associated with risk of type 2 diabetes (T2D) in women. Data of 3,117 postmenopausal women participants of the Rotterdam Study were analyzed to examine whether ESH and sex hormone-binding globulin (SHBG) were associated with the risk of incident T2D. Additionally, we performed a systematic review and meta-analysis of studies assessing the prospective association of ESH and SHBG with T2D in women. During a median follow-up of 11.1 years, we identified 384 incident cases of T2D in the Rotterdam Study...
March 2017: Diabetes
https://www.readbyqxmd.com/read/28214680/exploring-the-role-of-testosterone-in-the-cerebellum-link-to-neuroticism-from-adolescence-to-early-adulthood
#8
Dennis J L G Schutter, Rosa Meuwese, Marieke G N Bos, Eveline A Crone, Jiska S Peper
Previous research has found an association between a smaller cerebellar volume and higher levels of neuroticism. The steroid hormone testosterone reduces stress responses and the susceptibility to negative mood. Together with in vitro studies showing a positive effect of testosterone on cerebellar gray matter volumes, we set out to explore the role of testosterone in the relation between cerebellar gray matter and neuroticism. Structural magnetic resonance imaging scans were acquired, and indices of neurotic personality traits were assessed by administering the depression and anxiety scale of the revised NEO personality inventory and Gray's behavioural avoidance in one hundred and forty-nine healthy volunteers between 12 and 27 years of age...
January 29, 2017: Psychoneuroendocrinology
https://www.readbyqxmd.com/read/28185881/the-association-between-endogenous-testosterone-level-and-behavioral-flexibility-in-young-men-evidence-from-stimulus-outcome-reversal-learning
#9
Esther K Diekhof, Susanne Kraft
The capacity to flexibly adapt responding to unexpected changes in the environment is crucial for survival. Several neurotransmitters have been implicated in stimulus-outcome reversal learning. Yet, it remains an open question whether inter-individual differences in the neuroactive hormone testosterone may also be related to this type of behavioral flexibility. In this study we assessed the association between endogenous testosterone level and reversal learning in young healthy men. We used an observer reversal learning task, in which subjects viewed computer-based decisions between two stimuli, of which one was currently rewarded while the other one was punished...
February 20, 2017: Hormones and Behavior
https://www.readbyqxmd.com/read/28177387/evaluation-of-the-influence-of-prenatal-transportation-stress-on-gnrh-stimulated-luteinizing-hormone-and-testosterone-secretion-in-sexually-mature-brahman-bulls
#10
B P Littlejohn, M C Roberts, M N Bedenbaugh, A W Lewis, D A Neuendorff, D G Riley, J A Carroll, R C Vann, M Amstalden, R D Randel, T H Welsh
This study examined the relationship of prenatal transportation stress (PNS) with exogenous GnRH-induced LH and testosterone secretion in sexually mature Brahman bulls. Brahman cows (n = 96; 48 were stressed by transportation at 5 stages of gestation and 48 were controls) produced a calf crop of 85 calves. All bulls (n = 46) from this calf crop were electroejaculated every 2 wk beginning at a scrotal circumference of 24 cm until sexual maturity (SM; i.e., 500 million sperm/ejaculate). The initial 11 control and 12 PNS bulls to reach SM were selected for the experiment...
January 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28163248/associations-between-endogenous-sex-hormones-and-mri-structural-changes-in-patients-with-symptomatic-knee-osteoarthritis
#11
X Jin, B H Wang, X Wang, B Antony, Z Zhu, W Han, F Cicuttini, A E Wluka, T Winzenberg, L Blizzard, G Jones, C Ding
OBJECTIVE: To investigate the longitudinal association between endogenous sex hormones and knee osteoarthritis (OA) structures and pain. METHOD: We examined 200 participants (mean age 63.0 ± 7.3 years) from a clinical trial of vitamin D supplement for symptomatic knee OA. Serum levels of estradiol, progesterone, testosterone and sex hormone binding globulin (SHBG) were analyzed at baseline and 24 months later. Magnetic resonance imaging (MRI) scans of selected knee were obtained at both baseline and follow-up for the measurement of cartilage volume, cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis volume...
February 2, 2017: Osteoarthritis and Cartilage
https://www.readbyqxmd.com/read/28154797/sex-specific-effects-of-serum-sulfate-level-and-slc13a1-nonsense-variants-on-dhea-homeostasis
#12
Christina G Tise, Leslie E Anforth, Albert E Zhou, James A Perry, Patrick F McArdle, Elizabeth A Streeten, Alan R Shuldiner, Laura M Yerges-Armstrong
CONTEXT: Sulfate is critical in the biotransformation of multiple compounds via sulfation. These compounds include neurotransmitters, proteoglycans, xenobiotics, and hormones such as dehydroepiandrosterone (DHEA). Sulfation reactions are thought to be rate-limited by endogenous sulfate concentrations. The gene, SLC13A1, encodes the sodium-sulfate cotransporter NaS1, responsible for sulfate (re)absorption in the intestines and kidneys. We previously reported two rare, non-linked, nonsense variants in SLC13A1 (R12X and W48X) associated with hyposulfatemia (P = 9 × 10(- 20))...
March 2017: Molecular Genetics and Metabolism Reports
https://www.readbyqxmd.com/read/28141664/free-androgen-index-as-a-determinant-of-arterial-stiffness-in-menopause-a-mediation-analysis
#13
Irene Lambrinoudaki, Georgios A Georgiopoulos, Fani Athanasouli, Elena Armeni, Demetrios Rizos, Areti Augoulea, Sofia Chatzidou, Evangelia Koutli, Nikolaos Makris, Ioannis Kanakakis, Kimon Stamatelopoulos
OBJECTIVE: Associations of endogenous androgens in menopause with blood pressure (BP) and indices of arterial stiffness are reported, but directional relationships are not clear. Structural equation modeling is a contemporary statistical method, which allows assessment of such relationships and improves pathway understanding. METHODS: We recruited 411 consecutive apparently healthy postmenopausal women who underwent noninvasive vascular evaluation. This included pulse wave analysis (aortic pressures and arterial wave reflections [augmentation index]), measurement of aortic stiffness by pulse wave velocity (PWV), stiffness index (SI), and flow-mediated dilatation...
January 30, 2017: Menopause: the Journal of the North American Menopause Society
https://www.readbyqxmd.com/read/28129603/metabolomics-for-informing-adverse-outcome-pathways-androgen-receptor-activation-and-the-pharmaceutical-spironolactone
#14
J M Davis, D R Ekman, D M Skelton, C A LaLone, G T Ankley, J E Cavallin, D L Villeneuve, T W Collette
One objective in developing adverse outcome pathways (AOPs) is to connect biological changes that are relevant to risk assessors (i.e., fecundity) to molecular and cellular-level alterations that might be detectable at earlier stages of a chemical exposure. Here, we examined biochemical responses of fathead minnows (Pimephales promelas) to inform an AOP relevant to spironolactone's activation of the androgen receptor, as well as explore other biological impacts possibly unrelated to this receptor. Liquid chromatography with high resolution mass spectrometry (LC-MS) was used to measure changes in endogenous polar metabolites in livers of male and female fish that were exposed to five water concentrations of spironolactone (0, 0...
March 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28078222/testosterone-replacement-therapy-and-the-heart-friend-foe-or-bystander
#15
REVIEW
David S Lopez, Steven Canfield, Run Wang
The role of testosterone therapy (TTh) in cardiovascular disease (CVD) outcomes is still controversial, and it seems will remain inconclusive for the moment. An extensive body of literature has investigated the association of endogenous testosterone and use of TTh with CVD events including several meta-analyses. In some instances, a number of studies reported beneficial effects of TTh on CVD events and in other instances the body of literature reported detrimental effects or no effects at all. Yet, no review article has scrutinized this body of literature using the magnitude of associations and statistical significance reported from this relationship...
December 2016: Translational Andrology and Urology
https://www.readbyqxmd.com/read/28078217/testosterone-replacement-in-the-infertile-man
#16
REVIEW
Ahmad Majzoub, Edmund Sabanegh
Hypogonadism is a common clinical condition affecting men of different age groups. In addition to its sexual consequences, it has several implications posing significant concerns for a man's health and well-being. Recent advances in testosterone (T) supplementation have facilitated hypogonadism treatment. Despite that, patients complaining of infertility or seeking conception are still hindered by the unfavorable effects supplemental T has on testicular function. Consequently, alternative approaches that can stimulate endogenous T production are favored...
December 2016: Translational Andrology and Urology
https://www.readbyqxmd.com/read/28078215/off-label-therapies-for-testosterone-replacement
#17
REVIEW
Lorenzo DiGiorgio, Hossein Sadeghi-Nejad
The incidence of hypogonadism has been steadily increasing over the last few years. Exogenous testosterone has been the standard treatment for hypogonadal men, but is associated with suppression of spermatogenesis as well as other possible adverse effects. There are other medications, currently considered "off label" for androgen replenishment, that exert their effect through modulation of the hypothalamic-gonadal axis. These medications increase endogenous testosterone levels and offer a different therapeutic approach...
December 2016: Translational Andrology and Urology
https://www.readbyqxmd.com/read/28065723/social-context-dependent-relationships-between-mouse-dominance-rank-and-plasma-hormone-levels
#18
Cait M Williamson, Won Lee, Russell D Romeo, James P Curley
The associations between social status and endogenous testosterone and corticosterone have been well-studied across taxa, including rodents. Dominant social status is typically associated with higher levels of circulating testosterone and lower levels of circulating corticosterone but findings are mixed and depend upon numerous contextual factors. Here, we determine that the social environment is a key modulator of these relationships in Mus musculus. In groups of outbred CD-1 mice living in stable dominance hierarchies, we found no evidence of simple linear associations between social rank and corticosterone or testosterone plasma levels...
January 6, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28056433/pelvic-organ-prolapse-and-endogenous-circulating-sex-steroids-in-postmenopausal-women-a-case-control-study
#19
Barbara Bodner-Adler, Klaus Bodner, Cora Schneidinger, Oliver Kimberger, Ksenia Halpern, Heinz Koelbl, Wolfgang Umek
OBJECTIVE: We compared sex steroid levels of postmenopausal patients with symptomatic pelvic organ prolapse (POP) with postmenopausal matched patients without any sign of POP. Furthermore, we evaluated a possible relationship between sex steroid levels and various urogynecologic parameters in cases with POP. Main outcome of interest were differences in circulating estradiol levels between the two groups. STUDY DESIGN: We conducted a case-control study and 46 postmenopausal women with symptomatic POP≥stage 2 were matched 1:1 with 46 urogynecologic healthy women...
December 26, 2016: European Journal of Obstetrics, Gynecology, and Reproductive Biology
https://www.readbyqxmd.com/read/28054406/surfactant-protein-d-regulates-murine-testicular-immune-milieu-and-sperm-functions
#20
Sushama Rokade, Uday Kishore, Taruna Madan
PROBLEM: Surfactant protein D (SP-D), a pattern recognition protein that regulates inflammation and immune homoeostasis, is expressed by testicular germ cells under the influence of testosterone. This study investigates the role of SP-D in testicular immune privilege and sperm functions. METHOD OF STUDY: Testicular levels of cytokines and immunoregulatory molecules were evaluated in lipopolysaccharide (LPS)-challenged SP-D gene knockout mice (SP-D(-/-) ). Further, sperm functions were assessed by computer-assisted sperm analyser (CASA) and in vitro capacitation...
January 5, 2017: American Journal of Reproductive Immunology: AJRI
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