Read by QxMD icon Read

Testosterone synthesis

Sharada Mahalingam, Liying Gao, Jacqueline Eisner, William Helferich, Jodi A Flaws
Isoliquiritigenin is a botanical estrogen used as a dietary supplement. Previous studies show that other botanical estrogens affect ovarian estradiol synthesis, but isoliquiritigenin's effects on the ovary are unknown. Thus, this study tested the hypothesis that isoliquiritigenin inhibits ovarian antral follicle growth and steroidogenesis. Antral follicles from CD-1 mice were cultured with vehicle control (dimethyl sulfoxide; DMSO) or isoliquiritigenin (0.6μM, 6 μM, 36 μM, and 100 μM) for 48-96hours. During culture, follicle diameters were measured daily to assess follicle growth...
October 20, 2016: Reproductive Toxicology
Xueting Wang, Jie Ding, Zou Xiang, Peipei Jiang, Jing Du, Xiaodong Han
Microcystin-LR (MC-LR), which generates strong reproductive toxicity, reduces serum testosterone level without directly damaging Leydig cells. The purpose of this study was to identify the target cells of MC-LR in the rat hypothalamic-pituitary axis and to investigate the underlying mechanisms. We found that the gonadotropin-releasing hormone (GnRH) neurons were the direct target of MC-LR. In vivo results showed that upon exposure to rats, cells around the third ventricle of hypothalamus underwent apoptosis...
October 20, 2016: Toxicon: Official Journal of the International Society on Toxinology
E Kamanga-Sollo, K J Thornton, M E White, W R Dayton
In feedlot steers, estradiol-17β (E2) and combined E2 and trenbolone acetate (a testosterone analog) implants enhance rate and efficiency of muscle growth; and, consequently, these compounds are widely used as growth promoters in several countries. Treatment with E2 stimulates protein synthesis rate and suppresses protein degradation rate in fused bovine satellite cell (BSC) cultures; however, the mechanisms involved in these effects are not known with certainty. Although the genomic effects of E2 mediated through the classical estrogen receptors have been characterized, recent studies indicate that binding of E2 to the G protein-coupled estrogen receptor (GPER)-1 mediates nongenomic effects of E2 on cellular function...
September 13, 2016: Domestic Animal Endocrinology
Wen-Chyuan Chen, Yi-Ming Chen, Chi-Chang Huang, Yen-Dun Tzeng
Dehydroepiandrosterone (DHEA), the most abundant sex steroid, is primarily secreted by the adrenal gland and a precursor hormone used by athletes for performance enhancement. Whole-body vibration (WBV) is a well-known light-resistance exercise by automatic adaptations to rapid and repeated oscillations from a vibrating platform, which is also a simple and convenient exercise for older adults. However, the potential effects of DHEA supplementation combined with WBV training on to body composition, exercise performance, and hormone regulation are currently unclear...
2016: International Journal of Medical Sciences
Zachery R Reichert, Maha Hussain
The development of metastatic castration-resistant prostate cancer (mCRPC) signals the terminal disease phase. The preceding hormone-dependent disease setting is effectively managed with androgen deprivation therapy. This foundation of treatment has a high rate of biochemical and clinical response and meaningful clinical benefit but is finite in duration as most cancers will progress to castration resistance. Historically, treatment for mCRPC entailed androgen receptor (AR) inhibitors (nilutamide, flutamide, bicalutamide), nonspecific steroidal biosynthesis inhibitors (ketoconazole, itraconazole), steroids (prednisone, diethylstilbesterol, dexamethasone), or palliative chemotherapy (mitoxantrone, estramustine), but none of these strategies impacted survival...
September 2016: Cancer Journal
Sawa Horie, Akiko Yamaki, Shigeru Takami
Although several lines of evidence have suggested that sex steroids influence olfaction, little is known about the cellular basis of steroid-metabolizing enzymes in the olfactory system. Thus, we aimed to examine gene expression and immunolocalization of four sex steroid-metabolizing enzymes in the olfactory mucosa (OM) of albino rats; steroid side chain-cleaving enzyme (P450scc), 17β -hydroxysteroid dehydrogenase type 1 (17β -HSD-1), 17β -HSD type 2 (17β -HSD-2), and aromatase. P450scc is known to catalyze conversion from cholesterol to pregnenolone...
October 13, 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Edgar Flores-Soto, Jorge Reyes-García, Abril Carbajal-García, Elías Campuzano-González, Mercedes Perusquía, Bettina Sommer, Luis M Montaño
: Testosterone (TES), other androgens and female sex steroids induce non-genomic rapid relaxing effects in airway smooth muscle (ASM). In guinea pig ASM, basal tension was relaxed by dehydroepiandrosterone (DHEA) and TES; 17β-estradiol (E2) had a small effect. Blockers of L-type voltage dependent Ca(2+) channel (L-VDCC, D-600) and store operated Ca(2+) channel (SOC, 2-APB) also relaxed the basal tone. In tracheal myocytes, DHEA and TES diminished intracellular basal Ca(2+) concentrations (b[Ca(2+)]i) as D-600+2-APB but to a higher extend...
October 4, 2016: Molecular and Cellular Endocrinology
Rebecca Milsk, Jenna E Cavallin, Elizabeth J Durhan, Kathleen M Jensen, Michael D Kahl, Elizabeth A Makynen, Dalma Martinović-Weigelt, Nathan Mueller, Anthony Schroeder, Daniel L Villeneuve, Gerald T Ankley
The aim of this study was to investigate temporal changes in the hypothalamic-pituitary-gonadal (HPG) axis of fathead minnows (Pimephales promelas) treated with the model androgen receptor (AR) antagonist flutamide. Reproductively-mature fish were exposed in a flow-through test to analytically-confirmed concentrations of either 50 or 500μg flutamide/L for 8 d, followed by an 8-d recovery period in clean water. Fish were sampled at 1, 2, 4 and 8days during each phase of the experiment. Flutamide (500μg/L) caused significant reductions in relative gonad size of the females on day 8 of the exposure and day 1 of the recovery, and reduced expression of secondary sex characteristics in males during the exposure phase of the experiment...
October 1, 2016: Aquatic Toxicology
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
Lixian Cheng, Hui Shi, Yan Jin, Xiaoxi Li, Jinshun Pan, Yimei Lai, Yan Lin, Ya Jin, Gaurab Roy, Allan Zhao, Fanghong Li
Adipose tissue plays an important role in regulating female fertility owing to not only its energy stores but also the endocrine actions of secreted adipokines. As one of the adipokines, adiponectin is almost exclusively secreted from the fat and its circulating concentration is paradoxically reduced in obesity. Although recent studies implied a purported positive role of adiponectin in ovarian functions, definitive in vivo evidence has been sorely lacking. We have consistently observed subfertility in female adiponectin null mice, and therefore postulated a protective role of adiponectin in ovarian functions...
October 4, 2016: Endocrinology
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
Kathrine Eggers Pedersen, Robert J Letcher, Christian Sonne, Rune Dietz, Bjarne Styrishave
Per- and polyfluoroalkyl substances (PFASs) are emerging in the Arctic and accumulate in brain tissues of East Greenland (EG) polar bears. In vitro studies have shown that PFASs might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential PFAS induced alterations in brain steroid concentrations. The concentrations of eleven steroid hormones were determined in eight brain regions from ten EG polar bears. Pregnenolone (PRE), the dominant progestagen, was found in mean concentrations of 5-47ng/g (ww) depending on brain region...
September 27, 2016: Environment International
Ilona K Jóźwik, Flora M Kiss, Łukasz Gricman, Ammar Abdulmughni, Elisa Brill, Josef Zapp, Juergen Pleiss, Rita Bernhardt, Andy-Mark W H Thunnissen
: Cytochrome P450 monooxygenases (P450s) are attractive enzymes for the pharmaceutical industry, in particular, for applications in steroidal drug synthesis. Here, we report a comprehensive functional and structural characterization of CYP109E1, a novel steroid-converting cytochrome P450 enzyme identified from the genome of Bacillus megaterium DSM319. In vitro and whole-cell in vivo turnover experiments, combined with binding assays, revealed that CYP109E1 is able to hydroxylate testosterone at position 16β...
September 30, 2016: FEBS Journal
Mayumi Okamoto, Kyosuke Naka, Kiichi Ishiwata, Isao Shimizu, Jun Toyohara
OBJECTIVE: 7α-Substituted androgen derivatives may have the potential to visualize androgen receptors with positron emission tomography. In the present study, we synthesized fluoropropyl derivatives of 7α-(3-[(18)F]fluoropropyl)-testosterone ([(18)F]7) and 7α-(3-[(18)F]fluoropropyl)-dihydrotestosterone ([(18)F]15), and characterized their in vitro binding, in vivo biodistribution, and performed blocking studies in mature androgen deprived male rats. METHODS: We synthesized [(18)F]7 and [(18)F]15...
September 28, 2016: Annals of Nuclear Medicine
Noriko Kato, Tomomi Kusumi, Akihisa Kamataki, Rikiya Tsunoda, Masayuki Fukase, Akira Kurose
Sertoli-Leydig cell tumors (SLCTs) are representative of androgenic ovarian tumors, and they show diverse histologic differentiation, including heterologous differentiation. Genetically, SLCTs are characterized by the presence of DICER1 mutations. In the present study, we analyzed the correlation between somatic DICER1 hotspot mutations and clinicopathological features in 10 ovarian SLCTs. Six of the 10 (60%) SLCTs harbored a DICER1 hotspot mutation. Five of the 6 DICER1-mutated SLCT patients showed androgenic manifestations, including amenorrhea and hirsutism, and 4 of the 6 were associated with the significant elevation of serum testosterone...
September 21, 2016: Human Pathology
Joshua William Smith, Nikki A Ford, Jennifer M Thomas-Ahner, Nancy E Moran, Eric C Bolton, Matthew A Wallig, Steven K Clinton, John W Erdman
β-carotene-15,15'-dioxygenase (BCO1) cleaves dietary carotenoids at the central 15,15' double bond, most notably acting on β-carotene to yield retinal. However, Bco1 disruption also impacts diverse physiologic endpoints independent of dietary carotenoid feeding, including expression of genes controlling androgen metabolism. Using the Bco1(-/-) mouse model, we sought to probe the effects of Bco1 disruption on testicular steroidogenesis, prostatic androgen signaling, and prostatic proliferation. Male wild-type (WT) and Bco1(-/-) mice were raised on carotenoid-free AIN-93G diets before euthanasia between 10-14 weeks of age...
September 14, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Charles P Madenjian, Richard R Rediske, David P Krabbenhoft, Martin A Stapanian, Sergei M Chernyak, James P O'Keefe
A comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43 %. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females...
2016: Biology of Sex Differences
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
Michaël R Laurent, Christine Helsen, Leen Antonio, Dieter Schollaert, Steven Joniau, Michel J Vos, Brigitte Decallonne, Geoffrey L Hammond, Dirk Vanderschueren, Frank Claessens
Biochemical assessments of androgen status (hyper- or hypoandrogenism) are usually based on serum testosterone concentrations. According to the free hormone hypothesis, sex hormone-binding globulin (SHBG) determines free and bioavailable testosterone concentrations. Previous studies have suggested that in vitro androgen bioassay results may also be influenced by SHBG and correlate with free or bioavailable testosterone concentrations. To test this hypothesis, we established a stable HEK293 cell line with high expression of the human androgen receptor (AR) and a luciferase reporter downstream of a classical androgen response element...
December 5, 2016: Molecular and Cellular Endocrinology
Gabriela Cobo, Paloma Gallar, Cristina Di Gioia, Concepción García Lacalle, Rosa Camacho, Isabel Rodriguez, Olimpia Ortega, Carmen Mon, Ana Vigil, Bengt Lindholm, Juan Jesús Carrero
BACKGROUND: Testosterone deficiency (hypogonadism) is common among men undergoing haemodialysis, but its clinical implications are not well characterized. Testosterone is an anabolic hormone that induces erythrocytosis and muscle synthesis. We hypothesized that testosterone deficiency would be associated with low muscle mass, physical inactivity and higher dosages of erythropoietin-stimulating agents (ESA). METHODS: Single-center cross-sectional study of 57 male haemodialysis patients...
August 20, 2016: Nefrología: Publicación Oficial de la Sociedad Española Nefrologia
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"