Search results for "testosterone"

Cardiac autonomic function reveals adaptation to military training

2011

Abstract The last 4 weeks of basic military training are very stressful. We tested the hypothesis that changes in cardiac autonomic function during this period are associated with changes in maximal oxygen uptake and/or serum hormonal concentrations in male conscripts (n=22). Cardiac vagal autonomic function was assessed by measuring the high-frequency (0.15–0.4 Hz) spectral power of R–R intervals. Maximal oxygen uptake ([Vdot]O2max) and basal serum testosterone concentration were measured at the beginning and end of the period. Individual changes in vagally mediated high-frequency power (range −15% to +25%) correlated (r=0.73, P=0.001) with changes in [Vdot]O2max (range −9% to +6%) and cha…

Different hormonal response to continuous and intermittent exercise in middle-distance and marathon runners

2008

In order to study the effects of different athletic backgrounds on exercise-induced hormonal responses, serum testosterone, luteinizing hormone, follicle-stimulating hormone and cortisol concentrations were measured before and after intensive continuous and intermittent running in well-trained middle-distance runners (MID) and marathon runners (MAR). They performed two 40-min exercises on a treadmill: a continuous run at an intensity of 80% [tempo run (TR)] and an intermittent run (IR) at an intensity of 100% of the velocity associated with VO(2max). The testosterone response to IR and the cortisol response to TR was higher (P<0.05) in MID compared with MAR. The testosterone response to IR …

Screening of Ovarian steroidogenic pathway in Ciona intestinalis and its modulation after Tributyltin exposure

2010

In this study, we have identified several ovarian steroids in Ciona with high similarity to vertebrate steroids and showed that cholesterol, corticosterone, dehydroepiandrosterone, estrone, estradiol-17beta, testosterone, pregnenolone, progesterone, have identical molecular spectra with vertebrate steroids. In addition, we have studied the effects of an endocrine disruptor (tributyltin: TBT) on these sex hormones and their precursors, ovarian morphology, and gene expression of some key enzymes in steroidogenic pathway in the ovary of Ciona. Ovarian specimens were cultured in vitro using different concentrations of TBT (10{sup -5}, 10{sup -4} and 10{sup -3} M). Ethanol was used as solvent co…

ANABOLIC-ANDROGENIC STEROIDS SIGNALING

2012

Androgens exert their effects on various parts of the body, including muscles, bones, hair follicles in the skin, liver and kidney, reproductive, hematic, immune and nervous systems. The effects are modulated by specific cellular "steroid-converting" enzymes, located inside target tissues. All the anabolic steroids currently used are derivates of testosterone or changes of its structure. The most important esterified forms of testosterone include the propionate, cipionate, enhantate and undecanoate ones. The mechanism of action of AAS has not been fully elucidated and it is currently subject of many studies. Several mechanism of action have been proposed to identify the path activated by AA…

EFFECTS OF CONIUGATED LINOLEIC ACID ON TESTOSTERONE SYNTHESIS.

2011

Role of Testosterone in Male Sexual Impotent Patients

1985

The role of biological factors contributing to development of sexual dysfunction (SD) has given rise to controversy over many years. Whereas a broad consensus is achieved that schizophrenia and affective psychoses have a biological etiology, such mechanisms receive less acceptance for SD. Conversely, the observation that SD is frequently a concomitant factor in affective illness is subject of current interest in research. For both diseases SD and affective disorder impaired gonadal function is documented (Rubin et al., 1981; Benkert and Holsboer, 1984), whereas both disorders may well occur independantly from each other. In the following section we outline briefly some of the presently avai…

Low levels of testosterone levels increase the risk of major cardiovascular events in a follow-up to 5 years

2014

Materials and Methods. We evaluated a series of 802 patients with intermediate cardiovascular risk according to the Framingham Risk Score (FRS). The endothelial function through flow-mediated vasodilatation (FMD), the erectile function (EF), and the total serum testosterone levels were assessed. Patients were followed for up to 5 years and the prevalence and predictors of MACEs were evaluated. Results. The levels of serum testosterone are related with both endothelial function (FMD) (t=9,4080, 95% CI= 0,9318 to 1,4234, p<0,0001) and erectile function (FMD) (t=8,9584, 95% CI= 0,7642 to 1,1932, p<0,0001). Analysis of variance (ANOVA) of serum testosterone levels are related with the MACEs (F-…

Resolution of mixtures of steroidal hormones with micellar eluents of sodium dodecyl sulphate and acetonitrile or pentanol

2000

An optimization strategy was applied to explore the capability of hybrid micellar eluents of sodium dodecyl sulphate (SDS), using acetonitrile or pentanol as modifiers, to resolve mixtures of eleven steroids showing a wide range of hydrophobicity (clostebol acetate, dehydrotestosterone, dydrogesterone, medroxyprogesterone, medroxyprogesterone acetate, methandienone, methyltestosterone, progesterone, testosterone, testosterone enanthate and testosterone propionate). The accurate prediction of the retention behaviour of the steroids, with relative errors in the 0.8–1.7% and 0.4–2.9% ranges for SDS-acetonitrile and SDS-pentanol eluents, respectively, demonstrated the reliability of the methodo…

Retention-structure relationship studies for some steroidal hormones in micellar liquid chromatography

2000

The retention behavior in a C18 column of fourteen steroidal hormones (clostebol acetate, dehydrotestosterone, dydrogesterone, medroxyprogesterone, medroxyprogesterone acetate, methandienone, methyltestosterone, nandrolone, nandrolone decanoate, progesterone, testosterone, testosterone enanthate, testosterone propionate and, stanozolol) with pure micellar mobile phases prepared from sodium dodecyl sulfate (SDS), and hybrid mobile phases comprising SDS-acetonitrile and SDS-pentanol, was correlated with their octanol-water partition coefficients. Similar correlations were found with retention data obtained by other authors in gas chromatography, conventional reversed-phase liquid chromatograp…

DETERMINATION OF STEROIDAL HORMONES IN URINE SAMPLES BY MICELLAR LIQUID CHROMATOGRAPHY FOLLOWING SOLID-PHASE EXTRACTION

2001

Steroidal hormones were determined in spiked urine samples using micellar mobile phases of sodium dodecyl sulphate (SDS)-pentanol, solid-phase extraction (SPE), and detection in the UV region. In the optimized procedure, a 10 mL aliquot of urine sample is loaded into a C18 cartridge and washed with 2 mL of 50:50 (v/v) methanol-water, followed by 200 μL of 70:30 (v/v) methanol-water. The retained steroids are eluted with 2 mL of methanol and the eluate evaporated to dryness under nitrogen at 50°C. The residue is redissolved with 200 μL of the micellar mobile phase used in the chromatographic separation and injected into the chromatograph. The performance of the procedure was checked for 13 s…