Endogenous Testosterone

BACKGROUND: Dried blood spots have recently been approved by the World Anti-Doping Agency as an alternative biological matrix for testing of doping substances. However, their use is limited to the detection of non-threshold compounds without a Minimum Reporting Level due to the numerous issues related to quantitative analyses and the limitation on testing capabilities of a haemolysed matrix. AIM: In this study androstenedione, testosterone and IGF-1 were longitudinally monitored in four different blood matrices to evaluate the potential of liquid capillary blood as an alternative matrix for quantitative determination in doping control analysis...

Thyroid cancer (TC) is substantially more common in women than in men, pointing to a possible role of sex steroid hormones. We investigated the association between circulating sex steroid hormones, sex hormone binding globulin (SHBG) and the risk of differentiated TC in men and women within the European Prospective Investigation into Cancer and nutrition (EPIC) cohort. During follow-up, we identified 333 first primary incident cases of differentiated TC (152 in pre/peri-menopausal women, 111 in post-menopausal women, and 70 in men) and 706 cancer-free controls...

RATIONALE: High-resolution mass spectrometry (HRMS) has been demonstrated to be an alternative platform for quantitative analyses, identifying unknown compounds and gathering information for the elucidation of chemical structures. This work describes a method to detect 13 esters of testosterone (T) and 5 biomarkers in 0.1 mL of human serum using gas chromatography (GC) coupled to HRMS. METHODS: Analytes were extracted from serum after deproteinization and liquid-liquid extraction...

Leydig cell (LCs) apoptosis is responsible for decreased serum testosterone levels during late-onset hypogonadism (LOH). Our study was designed to illustrate the regulatory effect of lncRNA XIST on LCs and to clarify its molecular mechanism of action in LOH. The Leydig cells (TM3) was treated by 300 μM H2 O2 for 8 h to establish Leydig cell oxidative stress model in vitro. The expression levels of lncRNA XIST in the testicular tissues of patients with LOH were measured using fluorescence in situ hybridization (FISH)...

OBJECTIVE: This study aimed to determine whether concentrations of testosterone and its main precursor after menopause, dehydroepiandrosterone (DHEA), are associated with lipoproteins and other lipids in community-dwelling older women. METHODS: The Sex Hormones in Older Women (SHOW) study was an observational study of 6358 Australian women, aged at least 70 years, with no prior major adverse cardiovascular event who had sex hormones measured by liquid chromatography-tandem mass spectrometry...

My research focused on the effects of various drugs on (1) dopamine formation from p-tyramine catalyzed by polymorphic cytochrome P450 (CYP or P450) 2D6 variants and (2) endogenous steroid hormone hydroxylation catalyzed by CYP3A subfamily members (CYP3A4, CYP3A5, CYP3A7). The activation (cooperativity) of metabolic reactions catalyzed by P450s was especially emphasized. The effects of various psychotropic agents on dopamine formation from p-tyramine, catalyzed by wild-type CYP2D6.1 and CYP2D6 variants, including CYP2D6...

Oral fluid has gained significant interest as an alternative matrix for drug testing due to its easy and non-invasive collection. Despite these advantages, achieving suitably low limits of detection remains a clear challenge in the use of oral fluids for drug screening. In this study, we demonstrate that the application of commercially available SPME fibers followed by liquid chromatography tandem mass spectrometry can enable the comprehensive detection and confirmation of drugs in oral fluid samples. To this end, we develop and test a sample-preparation protocol for a panel of 46 drugs covering the most popular drugs of abuse and doping agents available worldwide...

BACKGROUND: Androgens are important sex hormones in both men and women and are supplemented when endogenous levels are low, for gender transitioning, or to increase libido. Androgens also circulate at higher levels in women with polycystic ovarian syndrome, a condition that increases the risk for cardiovascular diseases including hypertension and arterial stiffness. Since our previous work shows an important role for the G protein-coupled estrogen receptor (GPER) in arterial stiffness, we hypothesized that other hormones including androgens may impact arterial stiffness in female mice via downregulation of GPER...

For antidoping laboratories, the determination of an illicit testosterone (T) administration in urine samples remains a difficult process as it requires the determination of the exogenous origin by carbon isotope ratios (CIRs) of testosterone and its metabolites. As a complement to the urinary analysis, targeting testosterone esters (e.g. testosterone undecanoate [TU]) in serum samples by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) could represent a simpler approach compared with isotope ratio mass spectrometry (IRMS)...

BACKGROUND: Blood concentrations of testosterone and oestrone tend to increase in women aged >70 years, while concentrations of their precursor hormone dehydroepiandrosterone decline. It is unknown whether these changes influence physical function. We investigated whether concentrations of these hormones were associated with grip strength and self-reported physical function in community-dwelling older women. METHODS: 9179 Australian women, aged >70 years, were recruited to the ASPREE trial...

BACKGROUND: The complex correlation between ethnicity and race, clinical hyperandrogenism as signified by hirsutism, and biochemical androgen concentrations in Polycystic Ovary Syndrome (PCOS) is poorly understood. STUDY OBJECTIVE: The study aims to define the correlation between ethnicity/race and hirsutism score in patients with PCOS. METHODS: We conducted a retrospective chart review of a total of 251 patients with PCOS at the time of diagnosis...

BACKGROUND: In industrialized populations, low male testosterone is associated with higher rates of cardiovascular mortality. However, coronary risk factors like obesity impact both testosterone and cardiovascular outcomes. Here, we assess the role of endogenous testosterone on coronary artery calcium in an active subsistence population with relatively low testosterone levels, low cardiovascular risk and low coronary artery calcium scores. METHODOLOGY: In this cross-sectional community-based study, 719 Tsimane forager-horticulturalists in the Bolivian Amazon aged 40+ years underwent computed tomography (49...

BACKGROUND: Endogenous steroid hormones have significant effects on inflammatory and immune processes, but the immunological activities of steroidogenesis precursors remain largely unexplored. METHODS: We conducted a systematic approach to examine the association between steroid hormones profile and immune traits in a cohort of 534 healthy volunteers. Serum concentrations of steroid hormones and their precursors (cortisol, progesterone, testosterone, androstenedione, 11-deoxycortisol and 17-OH progesterone) were determined by liquid chromatography-tandem mass spectrometry...

OBJECTIVE: Symptomatic hypogonadism discourages men from stopping anabolic-androgenic steroids (AAS). Some men illicitly take drugs temporarily stimulating endogenous testosterone following AAS cessation (post-cycle therapy; PCT) to lessen hypogonadal symptoms. We investigated whether prior PCT use was associated with the normalization of reproductive hormones following AAS cessation. METHODS: Retrospective analysis of 641 men attending a clinic between 2015-2022 for a single, nonfasting, random blood test <36 months following AAS cessation, with or without PCT...

Clomiphene is a selective estrogen receptor modulator. It is indicated for the treatment of female infertility issues but in sport, it can be misused to stimulate endogenous testosterone secretion in men. Therefore, it has been prohibited at all times by the World Anti-doping Agency. The aim of this study was to get data to be able to interpret concentrations in athletes. A healthy volunteer (male, 62 years-old) ingested a single therapeutic dose of clomiphene (Clomid™, 50 mg). Strands of hair (blond, 4 cm) were collected one month after the ingestion...

Testosterone may reduce pain in cisgender women and transgender men. Rodents can provide a useful model for investigating physiological effects of hormone therapy. To this end, continuous-release testosterone or blank (placebo) capsules were implanted s.c. into young adult female rats, and three weeks later rats were either ovariectomized or sham-ovariectomized. Testosterone treatment that mimicked previously reported endogenous levels in males eliminated estrous cycling and decreased uterine weight. Testosterone also significantly increased body weight and suppressed the increases in daily wheel running observed in placebo controls over time...

BACKGROUND: Anabolic androgenic steroids (AAS) are thought to increase venous thromboembolism (VTE) risk. OBJECTIVES: We investigated whether AAS influence coagulation parameters associated with VTE by assessing their changes during and after AAS use. METHODS: The HAARLEM study enrolled 100 male amateur athletes voluntarily starting an AAS cycle between 2015 and 2018. We measured procoagulant and anticoagulant protein levels, D-dimer levels, endogenous thrombin potential (ETP), and clot lysis time (CLT) at baseline and during 2 years of follow-up...

Phenethylamine (PEA) is a naturally occurring trace amine that acts as a modulator in the central nervous system. It is widely sold as a dietary supplement and advertised for its mood enhancing effects and should support weight loss. It is prohibited in sports and itemized as a stimulant on the Prohibited List issued by the World Anti-Doping Agency (WADA). After oral administration of PEA, its urinary concentration is found only slightly elevated while metabolites of PEA show a significant increase. Besides 2-(2-hydroxyphenyl)acetamide sulfate, especially phenylacetylglutamine (PAG) was found at significantly elevated urinary concentrations after the administration...

RATIONALE: Behavioral effects of testosterone depend on dose, acute versus sustained formulation, duration of administration, personality, genetics, and endogenous levels of testosterone. There are also considerable differences between effects of endogenous and exogenous testosterone. OBJECTIVES: This study was the secondary behavioral arm of a registered clinical trial designed to determine if testosterone protects against loss of lean body mass and lower-body muscle function induced by a severe energy deficit typical of sustained military operations...

Rosemary Leaves (Rosmarinus officinalis) gained importance as natural antioxidants which strengthen the endogenous antioxidant defenses through die. The present experience was designed to assess the protective effect of ethanolic extract of rosemary leaves on the adrenal gland and testicular toxicity in male rabbits exposed to Cypermethrin. Forty healthy male rabbits were distributed into four groups of 10 animals each; the animals were administered cypermethrin 66.5 mg/kg alone or concurrent with Rosemary extract in both dosages (100 and 200 mg/kg) for 45 days, and the blood samples were taken from all animals for estimation hormones indices, the Anaesthetized animals were euthanized and adrenal gland and testes were separated for histopathological analysis...