Search results for "testosterone"
showing 10 items of 420 documents
Expression of Na+-d-glucose cotransporter SGLT2 in rodents is kidney-specific and exhibits sex and species differences
2012
With a novel antibody against the rat Na+-d-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and prevented by testosterone treatment. In the renal BBM vesicles, the rSGLT1-independent uptake of [14C]-α-methyl-d-glucopyranoside was similar in females and males, suggesting functional contribution of…
Effects of heavy resistance/power training on maximal strength, muscle morphology, and hormonal response patterns in 60-75-year-old men and women.
2002
Eleven women (TRW; 64 ± 4 yrs) and ten men (TRM; 65 ± 5 yrs) participated in the strength/power training twice a week for 24 weeks. Basal concentrations of serum total and free testosterone, growth hormone (GH), dehydroepiandrosterone sulfate (DHEAS), cortisol and sex hormone binding globulin (SHBG) as well as acute responses of serum total and free testosterone, growth hormone (GH) were measured. Maximal 1RM strength in the squat, chair rise time and muscle fibre distribution and areas of type I and IIa and IIb of the vastus lateralis were also examined. 1RM squat increased in TRW by 26 (SDIO) % (p < .001), and in TRM by 35(7) % (p < .001) and chair rise time improved in both groups…
The Influence of Sex, of Castration in New-Born Males and of Androgen Treatment in New-Born Females on the Mouse-Killing Behaviour of the Rat
1979
AbstractThe results we have got on the mouse-killing behaviour of the rat point out the remarkable percentage difference between control males and control females, between integral males and males castrated at birth, and between normal females and females under the effects of androgens.Such results make us believe that the appearance of the killer behaviour is affected by the presence of testosterone in the first days of life of the rat.
Alterations of peripheral testosterone metabolism after induced hypoprolactinemia in patients with prostatic carcinoma
1979
In 12 patients with advanced prostatic carcinoma the effect of bromocriptine-induced hypoprolactinemia on the peripheral androgen metabolism was investigated after 3H-testosterone injection under conditions that each individual served as his own control. After a 5-day significant prolactin suppression, the elimination of 3H-label 1 h after testosterone injection was about 45% and equal to pre-bromocriptine values. The recovery of dihydrotestosterone separated by silica gel T.L.C., however, was significantly augmented, resulting in a marked decrease of the testosterone/dihydrotestosterone ratio from 12.2 to 6.3. This induced 5alpha-reductase activity after prolactin suppression is in accorda…
Cocaine-induced locomotor activity is enhanced by exogenous testosterone
2002
Anabolic-androgenic steroids are synthetic derivatives of testosterone, which are increasingly abused by adolescent populations who also abuse psychoactive substances. All these compounds lead to complex behavioral syndromes and the effects of their interactions remain unclear. The main aim of the present study was to determine the influence of testosterone on the locomotor activity-promoting effect of cocaine on male mice in an open field. In the three experiments, animals received two injections: firstly, testosterone or peanut oil, and secondly, cocaine or saline solution. In Experiments 1 and 2, testosterone (or oil) and cocaine (or saline) were injected 45 and 10 min, respectively, pri…
Serum hormone concentrations during prolonged training in elite endurance-trained and strength-trained athletes.
1989
A study of 1 year was performed on nine elite endurance-trained athletes (swimmers) and on eight elite strength-trained athletes (weightlifters) in order to examine the effects of training on the endocrine responses and on physical performance capacity. The measurements for the determination of serum hormone concentrations were performed at about 4-month intervals during the course of the year. The primary findings demonstrated that during the first and most intensive training period of the year in preparing for the primary competitions similar but statistically insignificant changes were observed in the concentrations of serum testosterone, free testosterone and cortisol in both the endura…
Effect of inhibiting carnitine biosynthesis on male rat sexual performance.
2008
l-carnitine has a documented role as a cofactor in cellular energy metabolism and fatty acid beta-oxidation pathways and it has also been considered to function in reproductive biology. We investigated whether decreasing concentrations of L-carnitine using an inhibitor of its biosynthesis, mildronate (3-(2,2,2-trimethylhydrazinium)-propionate), would influence the sexual behavior or sperm quality in male rats. Mildronate treatment induced a significant decrease in carnitine concentration and an increase in gamma-butyrobetaine (GBB) concentration in both plasma and testes extracts. However, the expression of carnitine palmitoyltransferase I in testes and testosterone concentration in plasma …
Recovery from a national collegiate athletic association division I football game: muscle damage and hormonal status.
2008
The purpose of this study was to examine markers of skeletal muscle tissue damage and circulating anabolic and catabolic hormones to gain insight into the recovery process from Friday until Monday, when a new practice week begins. Twenty-eight National Collegiate Athletic Association Division I football players gave consent to participate in the investigation in the ninth game of the season. Sixteen players started the game and played the entire game (PL), and 12 others did not play and were on the bench during the game (DNP). Each player had fasted blood samples obtained at the same time of day between 1000 and 1200 hours the day before the game (Friday; T1), 18-20 hours after the game (Su…
Serum hormones and physical performance capacity in young boy athletes during a 1-year training period
1990
Serum hormones and physical performance capacity in boy athletes (AG; n = 19) were investigated during a 1-year training period (between the ages of 11.6 and 12.6 years). Six young untrained boys served as the control group (CG). The mean serum testosterone concentration increased significantly in AG (P less than 0.05) following the training period from 2.92 nmol.l-1, SD 1.04 to 5.81 nmol.l-1, SD 1.33. Significant differences were not observed in the cortisol, sex hormone binding globulin and growth hormone levels during the follow-up period. The AG clearly increased speed (P less than 0.001), speed-strength (P less than 0.01-P less than 0.001) and anaerobic capacity (P less than 0.001) whe…
Permissive and suppressive effects of dexamethasone on enzyme induction in hepatocyte co-cultures.
2002
1. Steroids are known to act as permissive factors in hepatocytes. This study shows that dexamethasone (DEX) is a permissive factor for induction of CYP2B1/2, CYP3A1, CYP2A1 and probably also CYP2C11 in cultures with primary rat hepatocytes. 2. The induction factor of phenobarbital (PB)-induced formation of 16beta-hydroxytestosterone (OHT), a testosterone biotransformation product predominantly formed by CYP2B1, is increased 18-fold by the addition of 32 nM DEX to the culture medium. Interestingly, higher concentrations of DEX up to 1000 nM led to a concentration-dependent maximally 5-fold decrease (p = 0.002) of phenobarbital-induced 16beta-OHT formation compared with the effect observed w…