Higher Plasma Testosterone Research Articles

Prenatal exposure to bisphenol S and bisphenol A differentially affects male reproductive system in the adult offspring

Early exposure to bisphenol may result in adverse reproductive health in later life. The use of bisphenol S (BPS) has increased considerably after bisphenol A (BPA) is regulated worldwide. However, little is known about the fetal exposure to BPS compared with BPA and its effects on the reproductive system in the adult male offspring. Here, we investigated the effects of orally administered BPS and BPA (0.4, 4.0, 40.0 μg/kg bw/d) during gestation (gD4-21) on testicular development by evaluating the sperm DNA damage & methylation and testicular functions in the 90 d Wistar rats. Male offspring prenatally exposed to BPS (0.4 μg/kg) had higher plasma testosterone than BPA and control. The testis histology reveals thickened membrane by producing a wide interstitial gap between seminiferous tubules, increased testicular inflammation, oxidative stress, TIMP-1 expression, and decreased VCAM-1 expression. BPS promotes apoptosis by up-regulating IL-6, cleaved caspases, and a spike in sperm DNA fragmentation. Prenatal BPS exposure reduces sperm motility mediated via impaired PI3K-AKT signaling and increases testicular TEX11 expression in the offspring. Exposure of the fetus to BPS interferes developmental programming of the male reproductive system in the offspring. BPS could be an equally potent endocrine disruptor affecting male reproductive functions.

Associations between plasma testosterone levels and season, nutritional status, age, and body size in free-ranging male Asian black bears (Ursus thibetanus) in central Honshu, Japan

Testosterone is an important regulator of male reproduction in terms of spermatogenesis and physiological changes in the accessory reproductive organs. Despite the important role of the testosterone level in male reproduction, testosterone levels vary among male bears even during the breeding season, and the causative underlying factors remain unknown. We postulated that testosterone levels are higher during the breeding season than during other seasons in free-ranging male bears, and that testosterone levels increase with advancing age, larger body size, and better nutritional status. We assessed potential factors (season, time of sampling, body condition index, head circumference, and age) associated with the testosterone level in 80 blood samples collected from free-ranging Asian black bears (Ursus thibetanus) captured in barrel traps in the Ashio–Nikko Mountains and Okutama Mountains in central Honshu Island, Japan. The plasma testosterone level was higher during the breeding season (May–July) than during the non-breeding season (August–November). The body condition index was significantly and positively associated with the plasma testosterone level. None of the other factors were significantly associated with the plasma testosterone level. Therefore, the body condition index may be essential for maintaining high plasma testosterone levels. These findings imply that testosterone secretion might be activated in free-ranging males during the breeding season, and animals with good nutritional status may be able to maintain high plasma testosterone levels. This study uncovered an association between nutritional conditions and reproductive activity in male bears.

Nocturnal One-Hour Lighting Stimulates Gonadal Development and Lowers Fat Deposition in Male Mule Ducks.

Simple SummaryPhotoperiods can affect sexual maturity, body weight, and body composition. In this work, we provided male mule ducks with a one-hour lighting from 20:00 to 21:00, in addition to the natural photoperiod, and evaluated its effects on their body weight, organ mass, gonadal function, and plasma levels of metabolites. The results indicate that the nocturnal lighting stimulated gonadal development and function and reduced fat deposition. This implies that nocturnal lighting is able to shorten the feeding period for the marketing of mature ducks. In this study, the effects of a nocturnal light pulse on body weight, organ mass, gonadal function, and plasma levels of metabolites were determined in male mule ducks. In total, 32 15-week-old mule ducks were randomly allocated to either Group C (control group) or L+ (lighting group). Group C was exposed to the natural photoperiod, whereas Group L+ was provided with a 1-h lighting over 20:00–21:00 every day, in addition to the natural photoperiod. At the end of the 42-day experiment, Group L+ had significantly lower relative weights (% of live weight) of the digestive tract and abdominal fat and higher relative weights of the breast meat and testes than Group C. Moreover, Group L+ had significantly higher plasma testosterone and lower plasma glucose levels. However, no between-group differences were observed in the triacylglycerol and uric acid levels. Histological examination demonstrated that the seminiferous tubule diameter was larger in Group L+ than in Group C. Moreover, the meiosis stage in spermatogenesis had begun in Group L+ but not in Group C. In conclusion, the supplemented 1-h lighting at 20:00 stimulated gonadal development and function and reduced fat deposition.

Psychosocial job factors and symptoms from the locomotor system--a multicausal analysis

The effects of physical and psychosocial work environment factors on emotions, psychosomatic and endocrine (cortisol and testosterone) states, back pain, symptoms of degenerative joint disease, and absenteeism for sickness, were studied in 147 men and 60 women in six occupations representing widely different physical and psychological activities. In most subjects, measurements were carried out twice to four times over one year. Statistical analyses were performed of the associations between different factor levels, such as age, gender, height, body mass index, and physical stressors at work. It was found that psychological work demands were associated with physiological indicators of strain (plasma cortisol and self-reported muscle tension) and that self-reported muscle tension was associated with several emotional reactions as well as with symptoms from the back, neck and shoulders. Little possibility for decision-making was associated with a high rate of absenteeism for sickness. In men, a high plasma testosterone level was associated with self-reported muscle tension. The results indicate that work environment factors influence mood, bodily tension and somatic symptoms, but that load on the locomotor system and opportunity to influence decisions play an important and more direct role in absenteeism for sickness

Concentrated ambient PM2.5exposure affects mice sperm quality and testosterone biosynthesis

BackgroundStudies suggested that PM2.5 exposure could lead to adverse reproductive effects on male animals. However, the underlying mechanism is still not clear. Besides, animals in the majority of previous studies were exposed to PM2.5 through intratracheal instillation which should be improved. In addition, limited amount of research has been conducted in China where the PM2.5 concentration is higher and the PM2.5 components are different. The aim of this work is to explore the effects of concentrated ambient PM2.5 (CAP) on mice sperm quality and testosterone biosynthesis.MethodsA total of 12 male C57BL/6 mice were exposed to filtered air (FA) or CAP for 125 days using the Shanghai Meteorological and Environmental Animal Exposure System. The mice sperm concentration, sperm motility, DNA fragmentation index, high DNA stainability and plasma testosterone were analyzed. Testicular histology and sperm morphology were observed through optical microscope. Testosterone biosynthesis related gene expressions were analyzed using real-time PCR, including cytochrome P450 CHOL side-chain cleavage enzyme (P450scc), steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β HSD), 17β-hydroxysteroid dehydrogenase, cytochrome P450 aromatase (P450arom), estrogen receptor (ER), androgen receptor (AR) and follicle stimulating hormone receptor (FSHR).ResultsExposure to CAP resulted in disturbance of various stages of spermatogenesis and significant higher percentage of abnormal sperm (FA vs. CAP: 24.37% vs. 44.83%) in mice testis. CAP exposure significantly decreased sperm concentration (43.00 × 106 vs. 25.33 × 106) and motility (PR: 63.58% vs. 55.15%; PR + NP: 84.00% vs. 77.08%) in epididymis. Plasma testosterone concentration were significantly declined (0.28 ng/ml vs. 0.69 ng/ml) under CAP exposure. Notably, the levels of testosterone biosynthesis related genes, StAR, P450scc, P450arom, ER and FSHR were significantly decreased with CAP exposure.ConclusionConcentrated ambient PM2.5 exposure altered mice sperm concentration, motility and morphology, which might be mediated primarily by the decline in testosterone concentration and testosterone biosynthesis process.

Gonad development and reproductive hormones of invasive silver carp (Hypophthalmichthys molitrix) in the Illinois River.

Reproduction is a major component of an animal's life history strategy. Species with plasticity in their reproductive biology are likely to be successful as an invasive species, as they can adapt their reproductive effort during various phases of a biological invasion. Silver carp (Hypophthalmicthys molitrix), an invasive cyprinid in North America, display wide variation in reproductive strategies across both their native and introduced ranges, though the specifics of silver carp reproduction in the Illinois River have not been established. We assessed reproductive status using histological and endocrinological methods in silver carp between April and October 2018, with additional histological data from August to October 2017. Here, we show that female silver carp are batch spawners with asynchronous, indeterminate oocyte recruitment, while male silver carp utilize a determinate pattern of spermatogenesis which ceases in the early summer. High plasma testosterone levels in females could be responsible for regulating oocyte development. Our results suggest that silver carp have high spawning activity in the early summer (May-June), but outside of the peak spawning period, female silver carp can maintain spawning-capable status by adjusting rates of gametogenesis and atresia in response to environmental conditions, while males regress their gonads as early as July. The results of this study are compared to reports of silver carp reproduction in other North American rivers as well as in Asia.

Endocrine and reproductive responses of male and female cattle to agonists of gonadotrophin-releasing hormone

The pituitary response in cattle to treatment with GnRH agonist has two phases. In the acute phase secretion of LH is increased, while the chronic phase is characterized by a downregulation of GnRH receptors and insensitivity of gonadotrophs to natural sequence GnRH. After long-term treatment with GnRH agonist, cattle do not have pulsatile secretion of LH but maintain basal LH. This is associated with reduced pituitary contents of LH, LH mRNA, FSH and FSH mRNA. Long-term treatment of bulls with GnRH agonist results in an increase in testicular LH receptors and high plasma testosterone. Heifers treated with a GnRH agonist from early in the oestrous cycle develop a larger corpus luteum and secrete more progesterone. Increased steroidogenesis is reflected in increased steroid acute regulatory (StAR) protein and steroidogenic enzymes in the testes and corpus luteum. GnRH agonists have potential as novel strategies for reproductive management in cattle. A GnRH agonist bioimplant was recently used to block the LH surge after FSH stimulation of follicle growth in heifers. Ovulation was induced by injection of LH, and heifers were inseminated relative to the LH injection. This GnRH agonist-LH protocol provides a model for studying the gonadotrophin requirements for follicular growth and oocyte maturation in cattle, and will enable controlled in vivo maturation of oocytes before recovery for in vitro procedures.

Effects of quantitative trait loci determining testicular weight in DDD/Sgn inbred mice are strongly influenced by circulating testosterone levels.

ObjectiveTesticular growth and development are strongly influenced by androgen. Although both testis weight and plasma testosterone level are inherited traits, the interrelationship between them is not fully established. Males of DDD/Sgn (DDD) mice are known to have extremely heavy testes and very high plasma testosterone level among inbred mouse strains. We dissected the genetic basis of testis weight and analyzed the potential influence of plasma testosterone level in DDD mice.MethodsQuantitative trait loci (QTL) mapping of testis weight was performed with or without considering the influence of plasma testosterone level in reciprocal F2 intercross populations between DDD and C57BL/6J (B6) mice, thereby assessing the influence of testosterone on the effect of testis weight QTL. Candidate genes for testis weight QTL were investigated by next-generation sequencing analysis.ResultsFour significant QTL were identified on chromosomes 1, 8, 14, and 17. The DDD-derived allele was associated with increased testis weight. The F2 mice were then divided into two groups according to the plasma testosterone level (F2 mice with relatively “low” and “high” testosterone levels), and QTL scans were again performed. Although QTL on chromosome 1 was shared in both F2 mice, QTL on chromosomes 8 and 17 were identified specifically in F2 mice with relatively high testosterone levels. By whole-exome sequencing analysis, we identified one DDD-specific missense mutation Pro29Ser in alpha tubulin acetyltransferase 1 (Atat1).ConclusionMost of the testis weight QTL expressed stronger phenotypic effect when they were placed on circumstance with high testosterone level. High testosterone influenced the QTL by enhancing the effect of DDD-derived allele and diminishing the effects of B6-derived allele. Since Pro29Ser was not identified in other inbred mouse strains, and since Pro29 in Atat1 has been strongly conserved among mammalian species, Atat1 is a plausible candidate for testis weight QTL on chromosome 17.

Rett Syndrome: Treatment with IGF-I, Melatonin, Blackcurrant Extracts, and Rehabilitation

(1) This study describes the good evolution of a 6-year-old girl genetically diagnosed (R106X) with Rett syndrome (RTT), after having been treated with IGF-I, melatonin (MT), blackcurrant extracts (BC) and rehabilitated for 6 months. (2) The patient stopped normal development in the first year of age. The patient showed short stature and weight and fulfilled the main criteria for typical RTT. Despite her young age, there was pubic hair (Tanner II), very high plasma testosterone, and low levels of plasma gonadotrophins. There were no adrenal enzymatic deficits, and abdominal ultrasound studies were normal. The treatment consisted of IGF-I (0.04 mg/kg/day, 5 days/week, subcutaneous (sc)) for 3 months and then 15 days of rest, MT (50 mg/day, orally, without interruption) and neurorehabilitation. A new blood test, after 3 months of treatment, was absolutely normal and the pubic hair disappeared (Tanner I). Then, a new treatment was started with IGF-I, MT, and BC for another 3 months. In this period, the degree of pubertal development increased to Tanner III (pubic level), without a known cause. (3) The treatment followed led to clear improvements in most of the initial abnormalities, perhaps due to the neurotrophic effect of IGF-I, the antioxidant effects of MT and BC, and the cerebral increase in the cyclic glycine-proline (cGP) achieved with administration of BC. (4) A continuous treatment with IGF-I, MT, and BC appears to be useful in RTT.

Abnormal lipid/lipoprotein metabolism and high plasma testosterone levels in male but not female aromatase-knockout mice

Sex steroid hormones, such as estrogen and testosterone, are believed to play important roles in lipid metabolism. To elucidate the effects of estrogen depletion on lipid metabolism in male and female mice, we used aromatase-knockout (ArKO) mice, in which Cyp19 gene disruption prevented estrogen synthesis in vivo. These mice were divided into the following 4 groups: male and female ArKO mice and male and female wild-type (WT) mice. These mice were fed a normal-fat diet (13.6% fat) ad libitum. At 159 days after birth, the mice were tested for liver and plasma lipid content and hepatic hormone receptor- and lipid/lipoprotein metabolism-related gene expression. Interestingly, we found that hepatic steatosis was accompanied by markedly elevated plasma testosterone levels in male ArKO mice but not in female ArKO mice. Plasma lipoprotein profiles exhibited concurrent decreases in LDL- and small dense LDL-triglyceride (TG) levels in male ArKO mice. Moreover, male mice, but not female mice, exhibited marked elevations in androgen receptor (AR), sterol regulatory element-binding protein 1 (SREBP1), and CD36 expression. These results strongly suggest that Cyp19 gene disruption, which induces a sexually dimorphic response and high plasma testosterone levels in male mice, also induces hepatic steatosis.

Seasonal changes in reproductive activity, sperm variables and sperm freezability in Blanca Andaluza bucks

Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001). No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05). After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05). These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer.

Correlation Between Personality Traits and Testosterone Concentrations in Healthy Population.

Objective:High plasma testosterone levels have been associated with aggression, sexual behaviour and social status. The aim of this paper was to study the correlation between basal plasma testosterone levels and personality variables in healthy participants.Materials and Methods:Fifty-four participants were randomly enrolled into this study. Basal plasma testosterone levels were measured between 8:30 am and 10 am. After 24 hours of blood drawing, each subject completed personality questionnaires.Results:Positive correlation between basal plasma testosterone levels and anti-social personality traits in both genders was observed (r = 0.336 and P < 0.018). Also, a positive correlation was observed between basal plasmatestosterone levels and criminal thinking traits (r = 0. 376, P < 0.05) and Millon compulsive (r = 0.386, P < 0.010) in both genders. In female participants, a positive correlation between basal plasmatestosterone levels and psychoticism (r = 0. 25, P < 0.019) and Cloninger AUTO TCI (r = 0.507, P < 0.004) was observed. In males participants positive correlation between baseline plasmatic Testosterone levels and Millon Antisocial trait (r = 0. 544, P < 0.19) and Millon Hypomania trait (r = 0. 485, P < 0.41) and Millon Drug Abuse trait (r = 0.632, P < 0.05) was reported.Conclusion:Our results suggest gender differences in clinical and personality variables related with basal plasma testosterone level. In men, high plasma testosterone levels were associated with clinical traits, substance abuse and hypomania. Women with higher basal testosterone levels showed higher scores on personality self-direction traits.

In older men, higher plasma testosterone or dihydrotestosterone is an independent predictor for reduced incidence of stroke but not myocardial infarction.

Older men have lower T levels, but whether differences in circulating T or its metabolites dihydrotestosterone (DHT) or estradiol (E2) contribute to cardiovascular disease remains controversial. We tested the hypothesis that plasma T, DHT, and E2 are differentially associated with the incidence of myocardial infarction (MI) and stroke in older men. Plasma total T, DHT, and E2 were assayed using liquid chromatography-mass spectrometry in early-morning samples from 3690 community-dwelling men aged 70-89 years. Outcomes of the first hospital admission or death due to MI or stroke were ascertained by data linkage. Mean follow-up was 6.6 years. Incident MI occurred in 344, stroke in 300, and neither in 3046 men. In a multivariate analysis adjusting for age and other risk factors, T, DHT, and E2 were not associated with incident MI [fully adjusted hazard ratio (HR) for T in quartile (Q) 4 vs Q1: 0.92, 95% confidence interval (CI) 0.66-1.28; DHT: 0.83, 95% CI 0.59-1.15; E2: 0.84, 95% CI 0.62-1.15]. Higher T or DHT was associated with a lower incidence of stroke (T: Q4: Q1 fully adjusted HR 0.56, 95% CI 0.39-0.81, P = .002; DHT: 0.57, 95% CI 0.40-0.81, P = .002). E2 was not associated with stroke (HR 0.76, 95% CI 0.54-1.08, P = .123). Higher plasma T or DHT is a biomarker for reduced risk of stroke but not MI. Androgen exposure may influence outcomes after rather than the incidence of MI, whereas androgens but not E2 are independent predictors of stroke risk. Randomized clinical trials are needed to clarify the impact of modifying T or DHT on the risk of stroke in aging men.

Predictors of Sexual Dysfunction Incidence and Remission in Men

The progress and determinants of sexual dysfunction in middle-aged and elderly men remain unclear. To describe the incidence or remission and biopsychosocial predictors of erectile dysfunction (ED) and low sexual desire (SD). Erectile function (International Index of Erectile Function) and sexual desire (Sexual Desire Inventory 2) were assessed at follow-up. Sociodemographic, lifestyle, and health-related factors were examined in multivariate models of ED and low SD. Data were collected from 810 randomly selected men residing in northern and western Adelaide, Australia, and aged 35-80 years at baseline, who made clinic visits 5 years apart. At baseline, 23.2% (n = 123) of men had ED. ED incidence and remission were observed in 31.7% (n = 179) and 29.0% (n = 71) of eligible men, respectively. At baseline, 19.2% (n = 165) had low solitary sexual desire, and 6.0% (n = 50) had low dyadic sexual desire; incidence of low sexual desire occurred in 17.6% (n = 83) (solitary) and 8.3% (n = 51) (dyadic), while remission occurred in 15.4% (n = 68) (solitary) and 22.6% (n = 40) (dyadic) of men. In the final regression models, predictors of incident ED were higher age, lower income, higher abdominal fat mass, low alcohol intake, higher risk of obstructive sleep apnea (OSA) risk, voiding lower urinary tract symptoms (LUTS), depression, and diabetes. Predictors of ED remission were lower age, current employment, and absence of voiding LUTS, angina, diabetes, and dyslipidemia. Predictors of low dyadic SD incidence included higher age, never having been married, widowhood, being unemployed, being retired, insufficient physical activity, and low alcohol intake. Predictors of low dyadic SD remission were being married, not being widowed, higher income, lower abdominal fat mass, lower OSA risk, and higher plasma testosterone. Predictors of low solitary SD included never having been married, being unemployed, low alcohol intake, lower testosterone, storage LUTS, and hypertension. Predictors of low solitary SD remission were being married, being employed, higher income, higher physical activity, moderate alcohol intake, and depression. Sexual dysfunction in aging men is a dynamic disorder whose incidence and remission are predicted by a range of modifiable risk factors.

Changes in the Immunolocalization of Steroidogenic Enzymes and the Androgen Receptor in Raccoon (&lt;i&gt;Procyon lotor&lt;/i&gt;) Testes in Association with the Seasons and Spermatogenesis

The raccoon is a seasonal breeder with a mating season in the winter. In a previous study, adult male raccoons exhibited active spermatogenesis with high plasma testosterone concentrations, in the winter mating season. Maintenance of spermatogenesis generally requires high testosterone, which is produced by steroidogenic enzymes. However, even in the summer non-mating season, some males produce spermatozoa actively despite low plasma testosterone concentrations. To identify the factors that regulate testosterone production and contribute to differences in spermatogenetic activity in the summer non-mating season, morphological, histological and endocrinological changes in the testes of wild male raccoons should be known. In this study, to assess changes in the biosynthesis, metabolism and reactivity of testosterone, the localization and immunohistochemical staining intensity of four steroidogenic enzymes (P450scc, P450c17, 3βHSD, P450arom) and the androgen receptor (AR) were investigated using immunohistochemical methods. P450scc and P450c17 were detected in testicular tissue throughout the year. Seasonal changes in testosterone concentration were correlated with 3βHSD expression, suggesting that 3βHSD may be important in regulating the seasonality of testosterone production in raccoon testes. Immunostaining of P450arom and AR was detected in testicular tissues that exhibited active spermatogenesis in the summer, while staining was scarce in aspermatogenic testes. This suggests that spermatogenesis in the raccoon testis might be maintained by some mechanism that regulates P450arom expression in synthesizing estradiol and AR expression in controlling reactivity to testosterone.

Seasonal Fluctuations of Sex Steroid Hormones in Indian Major Carp Catla Catla in Khouzestan, Iran

Catla (Catla catla) is one of the most important species of cyprinids in terms of economic and nutritional value that was considered as aquaculture candidate in Khozaestan province (Iran). In this study, 40 female and male Catla broodstocks (imported from India), were studied during year (summer 2011 to spring 2012). Seasonally, blood sampling was collected with heparinated syringe followed by catching and anesthesia. Levels of steroid hormones (testosterone, 17β-estradiol and progesterone) were measured by RIA. Results showed significant differences in all sex steroids during seasonal sampling (P<0.05). High plasma testosterone levels were measured in both sexes (female: 0.13 ± 0.03 ng/ml and male: 0.16 ± 0.04 ng/ml) in the course of the sexual maturation at the end of winter. Highest female plasma levels of 17 β-estradiol (128.50 ± 26.60 ng/ml) was measured in fall. Progesterone also significantly increased at winter (1.32 ± 0.22 ng/ml) in female broodstocks (P<0.05). All broodstocks were ripe and ready to breeding in winter. Water temperature was higth (29.88 ± 1.42) in summer which declined to (14.63 ± 0.47) in winter. According to the results, climatic conditions (Temperature) had a great impact on broodstocks Gonad development via involving of hormones in Khuzestan.

실내 사육한 줄가자미(Clidoderma asperrimum)의 성 성숙과 생식주기

The gonadosomatic index (GSI), sex steroid hormones and gonadal development of roughscale sole Clidoderma asperrimum cultured in indoor tank were investigated to evaluate its sexual maturation and reproductive cycle. The highest GSI values of female and male were <TEX>$6.91{\pm}4.03$</TEX> (May) and <TEX>$0.16{\pm}0.08$</TEX> (August), respectively. The reproductive cycle would be classified into four successive developmental stages: growing stage (December to February), maturation stage (March to April), ripe and spawning stage (May to June), recovery and resting stage (July to November). The highest plasma testosterone (T) and estradiol-<TEX>$17{\beta}$</TEX> (<TEX>$E_2$</TEX>) levels of female were <TEX>$259.4{\pm}76.8$</TEX> and <TEX>$633.3{\pm}182.5$</TEX> pg/mL, respectively in May. Also <TEX>$17{\alpha}$</TEX>, <TEX>$20{\beta}$</TEX>-dihydroxy-4-pregen-3-one (<TEX>$17{\alpha}$</TEX>, <TEX>$20{\beta}$</TEX>-OHP) levels of female peaked in April before spawning season (<TEX>$244.2{\pm}42.5$</TEX> pg/mL). The highest plasma testosterone (T) and 11-ketotestosterone levels of male were <TEX>$231.0{\pm}46.0$</TEX> and <TEX>$273.9{\pm}54.5$</TEX> pg/mL, respectively in April. But there was no significant difference in <TEX>$17{\alpha}$</TEX>, <TEX>$20{\beta}$</TEX>-OHP.

Testosterone secretion in elite adolescent swimmers does not modify bone mass acquisition: a 1-year follow-up study

To investigate whether high plasma testosterone (T) levels affect areal bone mineral density (aBMD), bone geometry, and bone remodeling in young elite female swimmers (SW). Cross-sectional and 1-year follow-up study. Pediatric endocrinology and gynecology units. Twenty-five SW and 21 control subjects (CON) with breast stages IV or V (mean age 15.3 ± 1.3 y). None. Clinical and biologic parameters, aBMD, and bone geometry. Two groups of SW were constituted on the basis of total T level. High T level SW (HSW; n = 15) presented higher T than SW with normal T (NSW; n = 10) and CON (0.63 ± 0.17; 0.36 ± 0.07, and 0.38 ± 0.14 ng/mL, respectively). The SHBG level (62.1 ± 18.7 vs. 43.3 ± 19.8 nmol/L) and the LH/FSH ratio (1.7 ± 1.1 vs. 0.9 ± 0.5) were higher, and menstrual disorders (60% vs. 23.8%) were more frequent in HSW than CON, and no difference was observed between the three groups for other sex hormones and insulin-like growth factor (IGF) 1 or IGF-binding protein 3. SW presented lower fat mass in the whole body and higher lean mass in the upper limbs only. aBMD was only modestly increased in the upper limbs in the SW groups, but no other bone-specific differences (aBMD, bone geometry, bone turnover markers) were demonstrated between SW and CON at baseline or for aBMD after 1 year in a subgroup of participants. High plasma T levels have no detectable effect on bone mass and bone geometry in SW during the period of peak bone mass acquisition.

Reproductive cycle of free-living male Saharan sand vipers, Cerastes vipera (Viperidae) in the Negev desert, Israel

The Saharan sand viper, Cerastes vipera (Linnaeus, 1758), is distributed in all Saharan countries, being confined to sand and dune systems. This relatively small snake, up to 35cm, is nocturnal, is active from spring to autumn (April to October) and hibernates during the winter (November to March). We predicted that C. vipera would have peak plasma testosterone concentration at mating and that the vas deferens would contain abundant spermatozoa at that time. To test our predictions, we collected information on the time of mating and measured monthly testosterone concentration, testes size and testicular activity in free-living male C. vipera during its active period from April to October. Mating occurred only during spring. The pattern of plasma testosterone concentration, testes volume, seminiferous tubule diameter and spermatogenesis all followed the general pattern of high values in autumn and spring and low values in early summer. Our predictions were partially supported. There was a high plasma testosterone concentration at mating in spring and the vas deferens contained abundant spermatozoa, as predicted, but there was also a high plasma testosterone concentration in autumn without mating. We concluded that: (1) males are both aestival in that they produce spermatozoa in autumn, which they store over the winter hibernation period, and vernal in that they produce spermatozoa in spring prior to mating; (2) matings are associated with spermatogenesis; and (3) the high plasma testosterone concentration is concomitant with both matings and spermatogenesis in spring and with spermatogenesis in autumn. We propose that C. vipera has a single peak of testicular activity and plasma testosterone concentration which start in autumn and end in spring. We also propose that spermatogenesis is prior to spring mating and, consequently, is prenuptial.

Influence of Sexual Stimulation and the Administration of Human Chorionic Gonadotrophin on Plasma Testosterone Levels in Dogs

The influence of sexual stimulation and human chorionic gonadotrophin (hCG) administration on plasma testosterone concentrations was assessed in five male Beagles. Each dog was exposed to three experimental treatments: C treatment (Control, no stimulation), hCG treatment (dogs were SC injected with 1000 IU of hCG) and sexually stimulated (SS) treatment where semen was collected from the males. All dogs were exposed to all treatments, one per week for three consecutive weeks, with a 1 week of rest between treatments. Blood samples were taken with the same time intervals (0, 10, 30, 60 and 120 min) relative to treatments. Plasma testosterone concentrations were determined with a solid-phase I(125) radioimmunoassay. In the control treatment, the testosterone plasma levels did not show significant changes throughout the tested period (mean values ranging between 2.8 and 4.7 ng/ml); the hCG group presented a significant increase (p < 0.05) in plasma testosterone levels 30 min after hCG administration and had the highest value (8.7 ng/ml) at 120 min post-hCG. Finally, the SS group revealed a slight reduction in testosterone concentration immediately after ejaculation, but the values remained nearly unaltered until 120 min after semen collection. When the groups were compared, the hCG group showed higher plasma testosterone values (p < 0.05) than did the C and SS groups, starting at 30 min and continuing until the end of sampling. This study demonstrates that sexual stimulation associated with semen collection does not produce transitory modifications in plasma testosterone concentrations.