Seasonal variation of salivary testosterone in men, normally cycling women, and women using hormonal contraceptives

Biomechanical and Biological Factors of Sexual Dimorphism in Anterior Knee Pain: Current Concepts

Female gender is one of the commonly mentioned risk factors for anterior knee pain (AKP), among a spectrum of other factors including anatomical, biomechanical, hormonal, behavioral, and psychological elements contributing to its development. Despite the focus on individual risk factors, there's a notable gap in comprehending how gender influences and interacts with other risk factors. The objective of this review was to identify and emphasize the connections between these interactions, gender-related risk factors for AKP, and the potential mechanisms that explain their associations with other risk factors, aiming to aid in the creation of precise prevention and treatment approaches. Gender influences the majority of risk factors for AKP, including anatomical, biomechanical, hormonal, behavioral, and psychological factors. Women have on average smaller patellae, higher patellofemoral cartilage stress and for AKP, disadvantageous trochlear morphology, ligament and muscle composition and unfavorable neuromuscular control pattern. In contrast, men show on average an increased ability to strengthen their hip external rotators, which are both protective against AKP. Particularly in kinetic and kinematic analysis, men have been shown to have a distinctly different risk factor profile than women. Sex hormones may also play a role in the risk of AKP, with estrogen potentially influencing ligamentous laxity, increasing midfoot loading and affecting neuromuscular control of the lower extremities and testosterone positively affecting muscle mass and strength. The higher incidence of AKP in women is likely due to a combination of slightly increased risk factors. Although all risk factors can be present in both men and women and the holistic evaluation of each individual's risk factor composition is imperative regardless of gender, knowing distinctive risk factors may help with focused evaluation, treatment, and implementing preventive measures of AKP.

Longitudinal changes in sexual desire and attraction among women who started using the Natural Cycles app

Many women experience sexual side effects, such as decreased libido, when taking hormonal contraceptives (HCs). However, little is known about the extent to which libido recovers after discontinuing HCs, nor about the timeframe in which recovery is expected to occur. Given that HCs suppress the activities of multiple endogenous hormones that regulate both the ovulatory cycle and women's sexual function, resumption of cycles should predict libido recovery. Here, using a combination of repeated and retrospective measures, we examined changes in sexual desire and partner attraction (among partnered women) across a three-month period in a sample of Natural Cycles users (Survey 1: n = 1596; Survey 2: n = 550) who recently discontinued HCs. We also tested whether changes in these outcomes coincided with resumption of the ovulatory cycle and whether they were associated with additional factors related to HC use (e.g., duration of HC use) or relationship characteristics (e.g., relationship length). Results revealed that both sexual desire and partner attraction, on average, increased across three months after beginning to use Natural Cycles. While the prediction that changes in sexual desire would co-occur with cycle resumption was supported, there was also evidence that libido continued to increase even after cycles resumed. Together, these results offer new insights into relationships between HC discontinuation and women's sexual psychology and lay the groundwork for future research exploring the mechanisms underlying these effects.

A multi-site study of the relationship between photoperiod and ovulation rate using Natural Cycles data

Many species exhibit seasonal patterns of breeding. Although humans can shield themselves from many season-related stressors, they appear to exhibit seasonal patterns of investment in reproductive function nonetheless, with levels of sex steroid hormones being highest during the spring and summer months. The current research builds on this work, examining the relationship between day length and ovarian function in two large samples of women using data from the Natural Cycles birth control application in each Sweden and the United States. We hypothesized that longer days would predict higher ovulation rates and sexual motivation. Results revealed that increasing day length duration predicts increased ovulation rate and sexual behavior, even while controlling for other relevant factors. Results suggest that day length may contribute to observed variance in women's ovarian function and sexual desire.

The future of sperm: a biovariability framework for understanding global sperm count trends

The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from 'Western' countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists' public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.

Are Sexual Desire and Sociosexual Orientation Related to Men's Salivary Steroid Hormones?

Objective

Although it is widely assumed that men’s sexual desire and interest in casual sex (i.e., sociosexual orientation) are linked to steroid hormone levels, evidence for such associations is mixed.

Methods

We tested for both longitudinal and cross-sectional relationships between salivary testosterone, cortisol, reported sexual desire and sociosexuality in a sample of 61 young adult men, each of whom was tested weekly on up to five occasions.

Results

Longitudinal analyses showed no clear relationships between steroid hormones and self-reported sexual desire or sociosexual orientation. Cross-sectional analyses showed no significant associations between average hormone levels and self-reported sexual desire. However, some aspects of sociosexuality, most notably desire for casual sex, were related to men’s average hormone levels. Men with higher average testosterone reported greater desire for casual sex, but only if they also had relatively low average cortisol levels.

Conclusions

Our results support a Dual Hormone account of men’s sociosexuality, in which the combined effects of testosterone and cortisol predict the extent of men’s interest in casual sex. However, we did not detect compelling evidence for an association of within-subject hormone shifts and sexual desire or sociosexual orientation.

Electronic supplementary material

The online version of this article (10.1007/s40750-020-00148-y) contains supplementary material, which is available to authorized users.

Is vitamin D status reflected by testosterone concentration in elite athletes?

Vitamin D is a nutrient whose active form affects tissues as a hormone and possibly enhances performance. One plausible mechanism is by increasing testosterone concentration, which is established as an important factor for athletic performance. Therefore the aim of the study was to examine the relationship between plasma concentration of 25(OH)D and testosterone in Polish elite track and field athletes depending on vitamin D status, season, training period, body composition, sex, type of training, sun exposure and vitamin D supplementation. Plasma concentrations of 25(OH)D and testosterone were measured in all seasons within two years in athletes (70 females, 79 males) who represent strength (n = 103) and endurance (n = 46) kinds of sports, in the preparatorycompetitive season and transition period. There were no differences in 25(OH)D concentration between male and female athletes, insufficiency [25(OH)D < 30 ng/ml] was observed in 32.9%, whereas deficiency [25(OH)D < 20 ng/ ml] in 3.2%. Circannual rhythm was noted for vitamin D but not for testosterone concentration; no correlations between them were found either in strength or endurance athletes or between 25(OH)D and body composition. Testosterone concentration was higher in the transition period than in the preparatory-competition period only in male athletes. Higher 25(OH)D was observed in athletes who trained during winter in Africa (higher sun exposure) or used oral supplementation, whereas the respective testosterone levels were unchanged. In athletes, testosterone concentration did not reflect vitamin D status. The widespread of inadequate vitamin D status among athletes, makes it vital to recommend them the regular monitoring of 25(OH)D concentration and use of reasonable supplementation.

Experimental empathy induction promotes oxytocin increases and testosterone decreases

Oxytocin and testosterone coordinate adaptive social behaviors with stimuli in the environment. Administration of oxytocin and testosterone is associated with increased and reduced indicators of empathy, respectively, but how levels of these hormones are jointly affected by naturalistic empathy-inducing stimuli remains unclear. In this study, salivary oxytocin and testosterone levels were measured in 173 healthy adults before and after watching a video involving a gravely ill child. Participants also completed questionnaires to assess psychological variables predicted to affect oxytocin reactivity (Autism-Spectrum Quotient, Interpersonal Reactivity Index, Empathy and Systemizing Quotients). On average, there was a 14% increase in oxytocin (p = 0.003) and 4% decrease in testosterone (p = 0.001) pre- to post-video. Opposite directional changes in hormone levels occurred together, as supported by a chi-square test (p < 0.001) and a circular statistics test (p < 0.05). Considered separately, psychological traits did not predict hormone levels or changes to any appreciable degree. However, oxytocin and testosterone changes were linked with empathy relative to systemizing such that: (1) 'Empathy Bias' was associated with a large oxytocin increase but little change in testosterone, while (2) 'Systemizing Bias' and 'Balance' between empathy and systemizing were associated with a decrease in testosterone but little change in oxytocin. These findings suggest that participants were divisible into 'high oxytocin responders' (relatively empathetic) and 'high testosterone responders' (balanced or systemizing-biased). These findings support a model of joint, opposite changes in oxytocin and testosterone under experimental empathy induction, with high, somewhat predictable, diversity in individual responses.

Low Daytime Light Intensity Disrupts Male Copulatory Behavior, and Upregulates Medial Preoptic Area Steroid Hormone and Dopamine Receptor Expression, in a Diurnal Rodent Model of Seasonal Affective Disorder

Seasonal affective disorder (SAD) involves a number of psychological and behavioral impairments that emerge during the low daytime light intensity associated with winter, but which remit during the high daytime light intensity associated with summer. One symptom frequently reported by SAD patients is reduced sexual interest and activity, but the endocrine and neural bases of this particular impairment during low daylight intensity is unknown. Using a diurnal laboratory rodent, the Nile grass rat (Arvicanthis niloticus), we determined how chronic housing under a 12:12 h day/night cycle involving dim low-intensity daylight (50 lux) or bright high-intensity daylight (1,000 lux) affects males’ copulatory behavior, reproductive organ weight, and circulating testosterone. We also examined the expression of mRNAs for the aromatase enzyme, estrogen receptor 1 (ESR1), and androgen receptor (AR) in the medial preoptic area (mPOA; brain site involved in the sensory and hormonal control of copulation), and mRNAs for the dopamine (DA) D1 and D2 receptors in both the mPOA and nucleus accumbens (NAC; brain site involved in stimulus salience and motivation to respond to reward). Compared to male grass rats housed in high-intensity daylight, males in low-intensity daylight displayed fewer mounts and intromissions when interacting with females, but the groups did not differ in their testes or seminal vesicle weights, or in their circulating levels of testosterone. Males in low-intensity daylight unexpectedly had higher ESR1, AR and D1 receptor mRNA in the mPOA, but did not differ from high-intensity daylight males in D1 or D2 mRNA expression in the NAC. Reminiscent of humans with SAD, dim winter-like daylight intensity impairs aspects of sexual behavior in a male diurnal rodent. This effect is not due to reduced circulating testosterone and is associated with upregulation of mPOA steroid and DA receptors that may help maintain some sexual motivation and behavior under winter-like lighting conditions.

Distribution of Salivary Testosterone in Men and Women in a British General Population-Based Sample: The Third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

Introduction:

Measurement of salivary testosterone (Sal-T) to assess androgen status offers important potential advantages in epidemiological research. The utility of the method depends on the interpretation of the results against robustly determined population distributions, which are currently lacking.

Aim:

To determine age-specific Sal-T population distributions for men and women.

Methods:

Morning saliva samples were obtained from participants in the third National Survey of Sexual Attitudes and Lifestyles, a probability sample survey of the British general population. Sal-T was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Linear and quantile regression analyses were used to determine the age-specific 2.5th and 97.5th percentiles for the general population (1675 men and 2453 women) and the population with health exclusions (1145 men and 1276 women).

Results:

In the general population, the mean Sal-T level in men decreased from 322.6 pmol/L at 18 years of age to 153.9 pmol/L at 69 years of age. In women, the decrease in the geometric mean Sal-T level was from 39.8 pmol/L at 18 years of age to 19.5 pmol/L at 74 years of age. The annual decrease varied with age, with an average of 1.0% to 1.4% in men and 1.3% to 1.5% in women. For women, the 2.5th percentile fell below the detection limit (<6.5 pmol/L) from age 52 years onward. The mean Sal-T level was approximately 6 times greater in men than in women, and this remained constant over the age range. The Sal-T level was lowest for men and highest for women in the summer. The results were similar for the general population with exclusions.

Conclusions:

To our knowledge, this is the first study to describe the sex- and age-specific distributions for Sal-T in a large representative population using a specific and sensitive LC-MS/MS technique. The present data can inform future population research by facilitating the interpretation of Sal-T results as a marker of androgen status.

Vitamin D and male reproductive system

Vitamin D deficiency is a highly prevalent worldwide condition and affects people of all ages. The most important role of vitamin D is the regulation of intestinal calcium absorption and metabolism of calcium and phosphorus to maintain muscle and bone homeostasis. Furthermore, in recent years it has been discovered that the vitamin D receptor (VDR) is widely distributed in many organs and tissues where vitamin D can perform other actions that include the modulation of the immune response, insulin secretion, anti-proliferative effect on cells of vascular smooth muscle, modulation of the renin-angiotensin-aldosterone system and regulates cell growth in several organs. The VDR is widely distributed in the male reproductive system. Vitamin D induces changes in the spermatozoa's calcium and cholesterol content and in protein phosphorylation to tyrosine/threonine residues. These changes could be involved in sperm capacitation. Vitamin D seems to regulate aromatase expression in different tissues. Studies analyzing seasonal variations of sex steroids in male populations yield conflicting results. This is probably due to the wide heterogeneity of the populations included according to age, systemic diseases and obesity.

Effects of two-year testosterone replacement therapy on cognition, emotions and quality of life in young and middle-aged hypogonadal men

The aim of the study was to examine the effects of two-year testosterone replacement therapy on cognitive functioning, emotional state and quality of life in young and middle-aged men with hypogonadotropic hypogonadism. Nineteen males diagnosed with hypogonadotropic hypogonadism participated in the study. Cognitive functions were assessed by Trail Making Test and Digit Span Test of Wechsler Adult Intelligence Scale. Emotional state was evaluated by Profile of Mood States. Quality of life was evaluated by WHO Brief Quality of Life Questionnaire. Changes after two-year testosterone replacement therapy were detected in Trail Making A (42.9 ± 22.3 vs. 36.2 ± 22.5, p = .050) and B (90.6 ± 55.3 vs. 65.6 ± 21.4, p = .025) tests, showing improvement in attention and visual scanning abilities, executive function and psychomotor speed, as well as in Digit Span Test forward score (5.4 ± 2.0 vs. 6.1 ± 2.6, p = .046), showing improvement in attention capacity and psychomotor speed. No significant differences were observed in emotional state and quality of life. In conclusion, beneficial effect in cognitive functioning (improved attention and visual scanning ability, executive function and psychomotor speed), but not in emotional state and quality of life, was observed in young and middle-aged hypogonadal men after two-year testosterone replacement therapy.

The effect of seasonal variation on sexual behaviors in males and its correlation with hormone levels: a prospective clinical trial

Introduction

We examined the effect of seasonal variation on sexual behavior and its relationship with testosterone levels. The existence of the inhibiting effect of cold stress on sexual behavior and testosterone levels was our hypothesis.

Material and methods

A total of 80 cases, aged between 20 and 35 years old, were enrolled. Blood samples for testosterone, FSH, LH, and prolactin were obtained twice from each participant at the same time of day (before 10 am). The first samples were taken in January and February, the months which have the average lowest heat days (-15.9°C and -14.6°C, respectively) in our region. The second samples were taken in July and August, which has the average highest heat days (25.4°C and 26.1°C, respectively) in our region. Two times IIEFs (International Index of Erectil Function) were fulfilled at the same day of taking blood samples. The frequency of sexual thoughts and ejaculation were questioned by asking “How many times did you imagine having sex?’’ and “How many times did you ejaculate in a week?”. The body mass index of the participants in the study was calculated in the winter and in the summer.

Results

There were significant differences in terms of IIEF scores, frequency of sexual thoughts and ejaculations, BMI (Body mass index), and both testosterone and FSH levels between the winter and summer measurements. We did not find any significant differences with regards to prolactin and LH levels.

Conclusions

Although testosterone levels are within normal limits in both seasons, its level in cold months is less than in hot months. Testosterone levels can change according to the season. The impact of cold seasons in particular should be taken into account when evaluating testosterone levels and sexual status, as well as the other influences (social, cultural).

Germ Cell Testicular Cancer Incidence, Latitude and Sunlight Associations in the United States and Australia

International patterns suggest germ cell testicular cancer (GCTC) incidence may be lower in lower latitudes. To investigate this possibility, we examined GCTC incidence by latitude (population centroid in 2000) for men ≥15 years within two reasonably homogeneous countries, the United States and Australia. In the United States, we examined age-adjusted incidence/latitude trends using data from states (2001-2010) and local-area registries (1980-2011). In Australia, we evaluated incidence/latitude trends in 61 Statistical Divisions (2000-2009). In U.S. White men (68 566 cases), state incidences increased by latitude, rising 5.74% (4.45-7.05%) per 5°North latitude increment. Similar trends were found for seminoma and nonseminoma subtypes (P < 0.001). In U.S. Black men (2256 cases), the association was also seen (4.9%; 0.2-9.7%). In local U.S. data, similar increases in incidence with latitude were present in each of the last three decades. In Australia (6042 cases), the incidence increased by 4.43% (95% CI: 1.54-7.39%) per 5°South, and trends for subtypes were similar. Thus, we found that incidence of GCTC in both White and Black men increased significantly with distance from the equator, approximately 1% per degree within the range of latitudes studied.

Genetic influences on pubertal development and links to behavior problems

Genetic influences on adolescent psychological development are likely to be mediated and moderated by pubertal hormones. Combining genetic analyses with advanced models of pubertal development, we extended work on the measurement and psychological significance of puberty. We examined how genetic and environmental influences on puberty vary by the way that development is described (logistic versus linear models versus traditional methods) and the different aspects of puberty (adrenarche vs. gonadarche), and how genes and environment contribute to the covariation between different descriptions and aspects of puberty, and between pubertal development and behavior problems (substance use, age at sexual initiation). We also considered how puberty moderated the heritability of psychological outcomes (internalizing and externalizing problems), and sex differences. Participants from the Colorado Longitudinal Twin Study (403 girls, 395 boys) reported their pubertal development annually from ages 9 through 15; they and their parents reported their behavior in mid-to-late adolescence. There was a large genetic contribution to pubertal timing for both sexes no matter how it was measured, but findings for pubertal tempo varied by method. Genetic covariation accounted for most of the phenotypic correlations among different indicators of pubertal timing, and between pubertal timing and psychological outcome. We consider the implications of our results for understanding how pubertal hormones mediate or moderate genetic and environmental influences on psychological development.

Confounding factors and genetic polymorphism in the evaluation of individual steroid profiling

In the fight against doping, steroid profiling is a powerful tool to detect drug misuse with endogenous anabolic androgenic steroids. To establish sensitive and reliable models, the factors influencing profiling should be recognised. We performed an extensive literature review of the multiple factors that could influence the quantitative levels and ratios of endogenous steroids in urine matrix. For a comprehensive and scientific evaluation of the urinary steroid profile, it is necessary to define the target analytes as well as testosterone metabolism. The two main confounding factors, that is, endogenous and exogenous factors, are detailed to show the complex process of quantifying the steroid profile within WADA-accredited laboratories. Technical aspects are also discussed as they could have a significant impact on the steroid profile, and thus the steroid module of the athlete biological passport (ABP). The different factors impacting the major components of the steroid profile must be understood to ensure scientifically sound interpretation through the Bayesian model of the ABP. Not only should the statistical data be considered but also the experts in the field must be consulted for successful implementation of the steroidal module.

Modeling pubertal timing and tempo and examining links to behavior problems

Research on the role of puberty in adolescent psychological development requires attention to the meaning and measurement of pubertal development. Particular questions concern the utility of self-report, the need for complex models to describe pubertal development, the psychological significance of pubertal timing vs. tempo, and sex differences in the nature and psychological significance of pubertal development. We used longitudinal self-report data to model linear and logistic trajectories of pubertal development, and used timing and tempo estimates from these models, and from traditional approaches (age at menarche and time from onset of breast development to menarche), to predict psychological outcomes of internalizing and externalizing behavior problems, and early sexual activity. Participants (738 girls, 781 boys) reported annually from ages 9 through 15 on their pubertal development, and they and their parents reported on their behavior in mid-to-late adolescence and early adulthood. Self-reports of pubertal development provided meaningful data for both boys and girls, producing good trajectories, and estimates of individuals' pubertal timing and tempo. A logistic model best fit the group data. Pubertal timing was estimated to be earlier in the logistic compared to linear model, but linear, logistic, and traditional estimates of pubertal timing correlated highly with each other and similarly with psychological outcomes. Pubertal tempo was not consistently estimated, and associations of tempo with timing and with behavior were model dependent. Advances in modeling facilitate the study of some questions about pubertal development, but assumptions of the models affect their utility in psychological studies.

The impact of sex hormone concentrations on decision-making in females and males

Human decision-making has been frequently studied and sex differences have been reported. Interestingly, previous results of hormone concentration on decision-making are somewhat inconsistent, regarding the impact of menstrual cycle phase in women or the influence of testosterone concentration on decision-making in women and men. However, the influence of the female sex hormone concentration (estradiol, progesterone) and the impact of oral contraceptive intake have rarely been examined and data regarding the effect of daytime variations of male testosterone are lacking. Moreover if personality factors such as sensation seeking, impulsivity, and anxiety influence decision-making, sex-specific effects, act as modulators is unclear. In the present study 71 women and 45 men were enrolled. All participants performed an evaluated decision-making task measuring risk-taking behavior on the basis of contingencies (Haegler et al., 2010), which can be carried out several times without a learning effect. Saliva samples were collected to obtain estradiol, progesterone, and testosterone levels. Additionally, all participants completed questionnaires measuring various personality factors. Data analysis revealed no sex differences in decision-making and no significant impact of testosterone concentration on behavioral performance in women or men. However, a significant negative correlation between progesterone concentration of women in the luteal phase and their performance in the risk-averse condition was obtained. Interestingly, a significant correlation between trait anxiety and decision-making occurred in females and males. Despite similar risky decision-making of women and men and no influence of testosterone concentration, menstrual cycle phase showed an effect on risk taking in women. In contrary to other studies, our findings provide rather subtle evidence for hormonal influences in decision-making, which may be primarily explained by task factors.

Seasonal trends in tinnitus symptomatology: evidence from Internet search engine query data

The primary aim of this study was to test the hypothesis that the symptom of tinnitus demonstrates a seasonal pattern with worsening in the winter relative to the summer using Internet search engine query data. Normalized search volume for the term 'tinnitus' from January 2004 through December 2013 was retrieved from Google Trends. Seasonal effects were evaluated using cosinor regression models. Primary countries of interest were the United States and Australia. Secondary exploratory analyses were also performed using data from Germany, the United Kingdom, Canada, Sweden, and Switzerland. Significant seasonal effects for 'tinnitus' search queries were found in the United States and Australia (p < 0.00001 for both countries), with peaks in the winter and troughs in the summer. Secondary analyses demonstrated similarly significant seasonal effects for Germany (p < 0.00001), Canada (p < 0.00001), and Sweden (p = 0.0008), again with increased search volume in the winter relative to the summer. Our findings indicate that there are significant seasonal trends for Internet search queries for tinnitus, with a zenith in winter months. Further research is indicated to determine the biological mechanisms underlying these findings, as they may provide insights into the pathophysiology of this common and debilitating medical symptom.

Measurement of testosterone in human sexuality research: methodological considerations

Testosterone (T) and other androgens are incorporated into an increasingly wide array of human sexuality research, but there are a number of issues that can affect or confound research outcomes. This review addresses various methodological issues relevant to research design in human studies with T; unaddressed, these issues may introduce unwanted noise, error, or conceptual barriers to interpreting results. Topics covered are (1) social and demographic factors (gender and sex; sexual orientations and sexual diversity; social/familial connections and processes; social location variables), (2) biological rhythms (diurnal variation; seasonality; menstrual cycles; aging and menopause), (3) sample collection, handling, and storage (saliva vs. blood; sialogogues, saliva, and tubes; sampling frequency, timing, and context; shipping samples), (4) health, medical issues, and the body (hormonal contraceptives; medications and nicotine; health conditions and stress; body composition, weight, and exercise), and (5) incorporating multiple hormones. Detailing a comprehensive set of important issues and relevant empirical evidence, this review provides a starting point for best practices in human sexuality research with T and other androgens that may be especially useful for those new to hormone research.

Effects of seasonal differences in testosterone and cortisol levels on pain responses under resting and anxiety conditions

PURPOSE

This study investigated whether hormones and pain perception are associated with exam anxiety, and also whether exam anxiety is affected by seasonal differences in testosterone and cortisol levels.

MATERIALS AND METHODS

Forty-six healthy males were recruited from a medical college. Anxiety was induced by having participants perform the Objective Structured Clinical Examination. Pressure was applied to the participants to induce pain. Pain thresholds, pain ratings, anxiety ratings, blood pressure, heart rate, salivary testosterone and cortisol levels were measured under resting and anxiety conditions in the spring and summer. Data were collected from 46 participants during the spring (n=25) and summer (n=21).

RESULTS

Pain thresholds and testosterone levels were significantly lower under anxiety than at rest for all participants (n=46), while cortisol levels, pain ratings, and anxiety ratings were significantly higher under anxiety than at rest. In the spring (n=25), testosterone levels were significantly higher at rest than under anxiety, while there was no difference in cortisol levels between resting and anxiety conditions. In the summer (n=21), cortisol levels were significantly higher under anxiety than at rest, while there was no difference in testosterone levels between resting and anxiety conditions. There were no significant seasonal differences in pain and anxiety ratings and pain threshold.

CONCLUSION

These results indicate that seasonal differences in testosterone and cortisol levels under anxiety and at rest may affect pain responses. These results also suggest that acute clinical pain may be relieved by managing anxiety that is related to a decrease of testosterone in spring and a large increase of cortisol in summer.

Time-course response in serum markers of bone turnover to a single-bout of electrical stimulation in patients with recent spinal cord injury

The objective of the present repeat-measures study was to determine whether plasma serum levels of testosterone, cortisol, osteocalcin or type I collagen C-telopeptide (CT) are acutely affected following an electro-myostimulation (EMS) bout, and their relation to bone mineral density and muscle mass. Ten men with recent (8 weeks) thoracic spinal cord injury (SCI) (ASIA A) and 10 age-matched able-bodied (AB) men performed one EMS bout on the quadriceps femoris muscle. Blood samples were drawn at basal condition, immediately after EMS, and 15 min, 30 min, 24 h and 48 h post-EMS. Muscle cross-sectional area was measured by magnetic resonance imaging. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry. In the SCI group, a significant decrease in testosterone, cortisol and CT together with a significant increase in testosterone/cortisol ratio and osteocalcin/CT ratio was observed after EMS. For the AB subjects, only testosterone and CT decreased significantly following EMS. Muscle size was only related to testosterone/cortisol ratio in the SCI sample (R = 0.659, p < 0.05), whereas BMD did not show any relation to any biomarker. Acute EMS in recent spinal cord injured men seems to induce positive effects on bone turnover biomarkers, and anabolic and catabolic hormones.

Testosterone and sport: current perspectives

Testosterone and other anabolic-androgenic steroids enhance athletic performance in men and women. As a result, exogenous androgen is banned from most competitive sports. However, due to variability in endogenous secretion, and similarities with exogenous testosterone, it has been challenging to establish allowable limits for testosterone in competition. Endogenous androgen production is dynamically regulated by both exercise and winning in competition. Furthermore, testosterone may promote athletic performance, not only through its long-term anabolic actions, but also through rapid effects on behavior. In women, excess production of endogenous testosterone due to inborn disorders of sexual development (DSD) may convey a competitive advantage. For many years, female competitors have been subject to tests of sexual genotype and phenotype known as gender verification. Although gender verification has not identified any normal man competing as a woman, this process has identified women athletes with DSD. As understanding of DSD has expanded in recent years, women with DSD are increasingly able to continue athletic competition.

Sex differences on the judgment of line orientation task: a function of landmark presence and hormonal status

It has been well-established that men outperform women on some spatial tasks. The tools commonly used to demonstrate this difference (e.g. The Mental Rotations Task) typically involve problems and solutions that are presented in a context devoid of referents. The study presented here assessed whether the addition of referents (or "landmarks") would attenuate the well-established sex difference on the judgment of line orientation task (JLOT). Three versions of the JLOT were presented in a within design. The first iteration contained the original JLOT (JLOT 1). JLOT 2 contained three "landmarks" or referents and JLOT 3 contained only one landmark. The sex difference on JLOT 1 was completely negated by the addition of three landmarks on JLOT 2 or the addition of one landmark on JLOT3. In addition, salivary testosterone was measured. In men, gains in performance on the JLOT due to the addition of landmarks were positively correlated with testosterone levels. This suggests that men with the highest testosterone levels benefited the most from the addition of landmarks. These data help to highlight different strategies used by men and women to solve spatial tasks.