Salivary testosterone determination in studies of child health and development

Genetic influences on adolescent sexual behavior: Why genes matter for environmentally oriented researchers

There are dramatic individual differences among adolescents in how and when they become sexually active adults, and early sexual activity is frequently cited as a cause of concern for scientists, policymakers, and the general public. Understanding the causes and developmental impact of adolescent sexual activity can be furthered by considering genes as a source of individual differences. Quantitative behavioral genetics (i.e., twin and family studies) and candidate gene association studies now provide clear evidence for the genetic underpinnings of individual differences in adolescent sexual behavior and related phenotypes. Genetic influences on sexual behavior may operate through a variety of direct and indirect mechanisms, including pubertal development, testosterone levels, and dopaminergic systems. Genetic differences may be systematically associated with exposure to environments that are commonly treated as causes of sexual behavior (gene-environment correlation). Possible gene-environment correlations pose a serious challenge for interpreting the results of much behavioral research. Multivariate, genetically informed research on adolescent sexual behavior compares twins and family members as a form of quasi experiment: How do twins who differ in their sexual experiences differ in their later development? The small but growing body of genetically informed research has already challenged dominant assumptions regarding the etiology and sequelae of adolescent sexual behavior, with some studies indicating possible positive effects of teenage sexuality. Studies of Gene × Environment interaction may further elucidate the mechanisms by which genes and environments combine to shape the development of sexual behavior and its psychosocial consequences. Overall, the existence of heritable variation in adolescent sexual behavior has profound implications for environmentally oriented theory and research.

Women's intercollegiate athletic competition: cortisol, testosterone, and the dual-hormone hypothesis as it relates to status among teammates

Recent research suggests that testosterone and cortisol jointly regulate dominance motivation and, perhaps, the status relationships that are affected by it. For this article, the results of six different studies of women's intercollegiate athletic competition were combined to give a sample size of almost ninety women for whom we had before- and after-competition values for salivary cortisol and testosterone for at least one and sometimes two competitions. For many of these women, we had surveys that allowed us to assess their status with teammates. In no matter what sport (soccer, softball, volleyball, and tennis) levels of salivary cortisol and testosterone increased when women participated in athletic competition. Salivary levels of C and T appear to rise in parallel during competition and increases in levels of one hormone are significantly related to increases in the other. Salivary levels of these hormones typically decreased for teammates who did not play but watched the competition from the sidelines. For women who played in two competitions, individual differences in the positive effect of competition on cortisol and testosterone were conserved from one competition to the next, affirming the personal consistency of endocrine responses to competition. Status with teammates was positively related to before-competition levels of testosterone, but only for women with relatively low before-competition levels of cortisol. This result provides novel support for the "dual-hormone hypothesis" as it relates to predicting social status in women's athletic teams - natural social groups of individuals who know each other and whose social hierarchy has evolved over the course of practice and play for at least one and, in some cases, several years of intercollegiate athletic competition.

The second-to-fourth digit ratio correlates with aggressive behavior in professional soccer players

The aim of this study was to test the hypothesis that high levels of testosterone during prenatal life, testified by a low second-to-fourth digit ratio (2D:4D), as well as in adulthood affect the aggressive behavior of professional soccer players. Using 18 male professional players from a first level Italian Soccer Team we calculated: i) the 2D:4D ratio of the right hand, ii) the number of yellow and red cards per game, iii) the mean salivary testosterone concentration (Sal/T) and iv) the handling of aggressive impulses as assessed by the Picture Frustration test (PFT). Soccer players with a lower 2D:4D ratio had a higher number of fouls per game. A significant negative correlation was observed between Sal/T and 2D:4D ratio, as well as between 2D:4D ratio and the aggressiveness of players. By contrast, a significant positive correlation of Sal/T and fouls/game score and PFT was detected. No significant correlation was detected between 2D:4D or Sal/T and the playing position of players. Results of this study revealed that in professional soccer players, aggressive behavior, with the consequent increased risk of fouls during the game, is more likely to occur in individuals with high testosterone levels, not only in adulthood, but also during their intrauterine life.

Steroid concentrations in antepartum and postpartum saliva: normative values in women and correlations with serum

Background

Saliva has been advocated as an alternative to serum or plasma for steroid monitoring. Little normative information is available concerning expected concentrations of the major reproductive steroids in saliva during pregnancy and the extended postpartum.

Methods

Matched serum and saliva specimens controlled for time of day and collected less than 30 minutes apart were obtained in 28 women with normal singleton pregnancies between 32 and 38 weeks of gestation and in 43 women during the first six months postpartum. Concentrations of six steroids (estriol, estradiol, progesterone, testosterone, cortisol, dehydroepiandrosterone) were quantified in saliva by enzyme immunoassay.

Results

For most of the steroids examined, concentrations in antepartum saliva showed linear increases near end of gestation, suggesting an increase in the bioavailable hormone component. Observed concentrations were in agreement with the limited data available from previous reports. Modal concentrations of the ovarian steroids were undetectable in postpartum saliva and, when detectable in individual women, approximated early follicular phase values. Only low to moderate correlations between the serum and salivary concentrations were found, suggesting that during the peripartum period saliva provides information that is not redundant to serum.

Conclusions

Low correlations in the late antepartum may be due to differential rates of change in the total and bioavailable fractions of the circulating steroid in the final weeks of the third trimester as a consequence of dynamic changes in carrier proteins such as corticosteroid binding globulin.

Hormonal predictors of sexual motivation in natural menstrual cycles

Little is known regarding which hormonal signals may best predict within- and between-women variance in sexual motivation among naturally cycling women. To address this, we collected daily saliva samples across 1-2 menstrual cycles from a sample of young women; assayed samples for estradiol, progesterone, and testosterone; and also collected daily diary reports of women's sexual behavior and subjective sexual desire. With respect to within-cycle, day-to-day fluctuations in subjective desire, we found evidence for positive effects of estradiol and negative effects of progesterone. Desire exhibited a mid-cycle peak, similar to previous findings; measured progesterone concentrations statistically mediated the fall in desire from mid-cycle to the luteal phase, but no combination of hormone measures substantially mediated the follicular phase rise in desire, which suggests that other signals may be implicated in this effect. Hormonal predictors of within-cycle fluctuations in sexual behavior generally reached only trend levels of statistical significance, though the patterns again suggested positive effects of estradiol and negative effects of progesterone. Between-women and within-women, between-cycle effects of hormone concentrations were generally absent, although statistical power was more limited at these higher levels of analysis. There were no significant effects of testosterone concentrations when controlling for the effects of estradiol and progesterone, which raises questions regarding the importance of this hormone for the regulation of sexual motivation in natural cycles. Our study is among the first to identify hormonal predictors of within-cycle fluctuations in sexual motivation, and thus adds novel evidence regarding the endocrine correlates of human sexuality.

Sexual development in prepubertal obese boys: a 4-year longitudinal study

The objective of the study was to evaluate whether or not sexual development differs between boys with prepubertal obesity and boys of normal weight. We enrolled healthy obese and normoweight schoolboys from Shenyang City, Liaoning, China. Eligible boys were at Tanner stage 1 and 8 years of age at baseline. We measured testosterone and estradiol concentrations in the saliva and assessed auxology annually for 4 years. In all 56 obese and 56 normoweight boys, the height, weight, body composition, and sex organ volume increased with age. The percentages of body fat, fat mass, and lean mass were all higher in obese than in normoweight boys. The mean testicular volume was smaller in obese boys than in normoweight boys. The sex hormone concentrations increased with age, except for testosterone in obese boys in year 3 of follow-up. In year 4, estradiol concentrations were significantly higher in obese boys than in normoweight boys. Excessive adiposity in prepubertal boys might affect testicular volume, possibly because of high estradiol and low testosterone concentrations.

Predicting Treatment Response for Oppositional Defiant and Conduct Disorder Using Pre-treatment Adrenal and Gonadal Hormones

Variations in adrenal and gonadal hormone profiles have been linked to increased rates of oppositional defiant disorder (ODD) and conduct disorder (CD). These relationships suggest that certain hormone profiles may be related to how well children respond to psychological treatments for ODD and CD. The current study assessed whether pre-treatment profiles of adrenal and gonadal hormones predicted response to psychological treatment of ODD and CD. One hundred five children, 6 - 11 years old, participating in a randomized, clinical trial provided samples for cortisol, testosterone, dehydroepiandrosterone, and androstenedione. Diagnostic interviews of ODD and CD were administered up to three years post-treatment to track treatment response. Group-based trajectory modeling identified two trajectories of treatment response: 1) a High-response trajectory where children demonstrated lower rates of an ODD or CD diagnosis throughout follow-up, and 2) a Low-response trajectory where children demonstrated higher rates of an ODD or CD diagnosis throughout follow-up. Hierarchical logistic regression predicting treatment response demonstrated that children with higher pre-treatment concentrations of testosterone were four times more likely to be in the Low-response trajectory. No other significant relationship existed between pre-treatment hormone profiles and treatment response. These results suggest that higher concentrations of testosterone are related to how well children diagnosed with ODD or CD respond to psychological treatment over the course of three years.

Chronotype but not sleep length is related to salivary testosterone in young adult men

Sex hormones, including testosterone, are hypothesized to have an influence on the human circadian system. We sampled male students in the period after adolescence. We used the Composite Scale of Morningness (CSM) to assess chronotype and saliva testosterone sampling in 106 University students (23.87±3.56 years; range 19-37) between 26.4.2011 and 6.5.2011, always between 0800h and 0900h. There was a significant negative relationship between CSM scores and saliva testosterone (r(s)=-0.220, p=0.023, two-tailed test) but not between testosterone and average sleep length. Age and testosterone did not correlate with each other nor did age and CSM scores. Our data suggest that chronotype in men might be influenced by testosterone and that high testosterone levels lead to a stronger evening-orientation. Sleep duration was uncorrelated with testosterone, suggesting that timing of sleep - rather than sleep length itself - is influenced by testosterone.

Associations between salivary testosterone and cortisol levels and neonatal health and growth outcomes

OBJECTIVES

Male vulnerability in health and growth outcomes has often been reported in very low birth weight (VLBW) preterm neonates. On the basis of gender-difference theories, possible associations were explored between the levels of postnatal salivary testosterone/cortisol and the outcomes of neonatal health/growth.

METHODS

This study used an exploratory and comparative research design. One-hundred-one mother-VLBW preterm neonate pairs were recruited from the neonatal intensive care unit (NICU) of a tertiary medical center in the Southeastern, US. Demographic information, health and growth variables of neonates, and pregnancy and labor variables of mothers were obtained from the medical record reviews and interviews of mothers. Saliva samples from each pair were collected between 9 and 60 days of age. The levels of testosterone and cortisol were determined by using an enzyme immunoassay methodology.

RESULTS

Linear regression analysis showed that neonatal health problems were positively associated with the levels of postnatal salivary testosterone and cortisol, while growth delays were positively associated with the levels of postnatal salivary testosterone after adjusting for the characteristics of neonates and mothers and day of saliva sampling. The salivary levels of testosterone and cortisol were higher in neonates than in mothers. A positive correlation between the levels of testosterone and cortisol was found in neonates and in mothers.

CONCLUSIONS

The level of postnatal salivary testosterone is a more reliable marker in assessing neonatal health and growth outcomes compared to salivary cortisol. Further research on both testosterone and cortisol measurements at various stages during the neonatal period may elucidate further these associations.

Soft song during aggressive interactions: seasonal changes and endocrine correlates in song sparrows

It is well known that songbirds produce high amplitude songs ("broadcast songs"). Songbirds also produce low amplitude songs ("soft songs") during courtship or territorial aggression in the breeding season. Soft songs are important social signals but have been studied far less than broadcast songs. To date, no studies have examined seasonal changes in soft song or its endocrine regulation. Here, in male song sparrows, we examined soft songs during a simulated territorial intrusion in the breeding season and non-breeding season. We also measured plasma testosterone and dehydroepiandrosterone (DHEA) levels in subjects immediately after the aggressive encounter. The total number of songs produced (broadcast+soft songs) did not vary between seasons. However, there was a dramatic increase in the percentage of soft song in the non-breeding season. Further, the percentage of soft song was negatively correlated with plasma testosterone levels in the non-breeding season. There were seasonal differences in the acoustic structure of two major elements of soft song, trills and buzzes. The minimum frequency of trills was lower in the non-breeding season, and the element repetition rate of buzzes was lower in the non-breeding season. To our knowledge, this is the first study to (1) examine soft songs outside of the breeding season and (2) to identify endocrine correlates of soft songs, which are important social signals in songbirds.

Evaluation of saliva collection devices for the analysis of proteins

BACKGROUND

Human saliva mirrors the body's health and can be collected non-invasively, does not require specialized skills and is suitable for large population based screening programs. The aims were twofold: to evaluate the suitability of commercially available saliva collection devices for quantifying proteins present in saliva and to provide levels for C-reactive protein (CRP), myoglobin, and immunoglobin E (IgE) in saliva of healthy individuals as a baseline for future studies.

METHODS

Saliva was collected from healthy volunteers (n=17, ages 18-33years). The following collection methods were evaluated: drool; Salimetrics® Oral Swab (SOS); Salivette® Cotton and Synthetic (Sarstedt) and Greiner Bio-One Saliva Collection System (GBO SCS®). We used AlphaLISA® assays to measure CRP, IgE and myoglobin levels in human saliva.

RESULTS

Significant (p<0.05) differences in the salivary flow rates were observed based on the method of collection, i.e. salivary flow rates were significantly lower (p<0.05) in unstimulated saliva (i.e. drool and SOS), when compared with mechanically stimulated methods (p<0.05) (Salivette® Cotton and Synthetic) and acid stimulated method (p<0.05) (SCS®). Saliva collected using SOS yielded significantly (p<0.05) lower concentrations of myoglobin and CRP, whilst, saliva collected using the Salivette® Cotton and Synthetic swab yielded significantly (p<0.05) lower myoglobin and IgE concentrations respectively.

CONCLUSIONS

The results demonstrated significantly relevant differences in analyte levels based on the collection method. Significant differences in the salivary flow rates were also observed depending on the saliva collection method. The data provide preliminary baseline values for salivary CRP, myoglobin, and IgE levels in healthy participants and based on the collection method.

Are There Useful Physiological or Psychological Markers for Monitoring Overload Training in Elite Rowers?

There is a need for markers that would help determine when an athlete’s training load is either insufficient or excessive. In this study we examined the relationship between changes in performance and changes in physiological and psychological markers during and following a period of overload training in 10 female and 10 male elite rowers. Change in performance during a 4-wk overload was determined with a weekly 30-min time-trial on a rowing ergometer, whereas an incremental test provided change in lactate-threshold power between the beginning of the study and following a 1-wk taper after the overload. Various psychometric, steroid-hormone, muscle-damage, and inflammatory markers were assayed throughout the overload. Plots of change in performance versus the 4-wk change in each marker were examined for evidence of an inverted-U relationship that would characterize undertraining and excessive training. Linear modeling was also used to estimate the effect of changes in the marker on changes in performance. There was a suggestion of an inverted U only for performance in the incremental test versus some inflammatory markers, due to the relative underperformance of one rower. There were some clear linear relationships between changes in markers and changes in performance, but relationships were inconsistent within classes of markers. For some markers, changes considered to predict excessive training (eg, creatine kinase, several proinflammatory cytokines) had small to large positive linear relationships with performance. In conclusion, some of the markers investigated in this study may be useful for adjusting the training load in individual elite rowers.

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.

Influence of treatment for disruptive behavior disorders on adrenal and gonadal hormones in youth

The study examined whether psychosocial intervention for children diagnosed with a disruptive behavior disorder (DBD; n = 84) changed concentrations of cortisol and testosterone across a 3-year follow-up when compared to a matched, nonclinical, healthy comparison (HC; n = 69) group. Boys and girls (6-11 years) with a DBD were randomly assigned to one of two arms of a multimethod intervention. Hierarchical linear modeling revealed that children undergoing psychosocial intervention for a DBD experienced a significant decline in diurnal cortisol change over time (p < .05) when compared to the HC condition. Boys with a DBD diagnosis had significantly lower mean cortisol concentrations prior to treatment (p < .05) and showed a significantly steeper increase in mean cortisol over time (p < .05) when compared to HC boys. Treatment effects for diurnal cortisol change were replicated in the boys-only analysis. No treatment effects were noted for testosterone in either analysis.

Parents' testosterone and children's perception of parent-child relationship quality

We examine the link between parental testosterone and children's perceptions of their relationship with their mother and father. Using data from 352 predominantly white working and middle class families, we find no direct link between mother's and father's testosterone and parent-child closeness. However, the association between mothers' testosterone and mother-child closeness appears to be influenced by the quality of two other family relationships. When father's marital satisfaction is low, mothers with high testosterone have a poorer relationship with their children. And, when fathers report low levels of intimacy with their children, high testosterone women have a poorer relationship with their children. No comparable associations were observed among fathers.

Genetic influences on hippocampal volume differ as a function of testosterone level in middle-aged men

The hippocampus expresses a large number of androgen receptors; therefore, in men it is potentially vulnerable to the gradual age-related decline of testosterone levels. In the present study we sought to elucidate the nature of the relationship between testosterone and hippocampal volume in a sample of middle-aged male twins (average age 55.8 years). We found no evidence for a correlation between testosterone level and hippocampal volume, as well as no indication of shared genetic influences. However, a significant moderating effect of testosterone on the genetic and environmental determinants of hippocampal volume was observed. Genetic influences on hippocampal volume increased substantially as a function of increasing testosterone level, while environmental influences either decreased or remained stable. These findings provide evidence for an apparent gene-by-hormone interaction on hippocampal volume. To the best of our knowledge, this is the first study to demonstrate that the heritability of a brain structure in adults may be modified by an endogenous biological factor.

Measurement of testosterone in infant fecal samples

OBJECTIVES

This study reports the validation of a noninvasive method for repeated assessment of testosterone from infant fecal samples.

METHODS

Fecal samples were collected from cotton diaper liners, subjected to methanol extraction, and assayed using a modified commercial testosterone RIA kit.

RESULTS

Method validity was supported by a recovery near 100%, a sensitivity of 1.23 pg/ml, and inter- and intra-assay coefficients of variations less than 10 and 15%, respectively. Testosterone was detected in all samples from male and female infants aged 2 weeks to 15 months.

CONCLUSIONS

Fecal assessment is supported as a novel, non-invasive tool for studying testosterone during early human development.

Men with elevated testosterone levels show more affiliative behaviours during interactions with women

Testosterone (T) is thought to play a key role in male-male competition and courtship in many vertebrates, but its precise effects are unclear. We explored whether courtship behaviour in humans is modulated and preceded by changes in T. Pairs of healthy male students first competed in a non-physical contest in which their T levels became elevated. Each participant then had a short, informal interaction with either an unfamiliar man or woman. The sex of the stimulus person did not affect the participants' behaviour overall. However, in interactions with women, those men who had experienced a greater T increase during the contest subsequently showed more interest in the woman, engaged in more self-presentation, smiled more and made more eye contact. No such effects were seen in interactions with other men. This is the first study to provide direct evidence that elevating T during male-male competition is followed by increased affiliative behaviour towards women.

Testosterone and romance: the association of testosterone with relationship commitment and satisfaction in heterosexual men and women

OBJECTIVES

The current study extends previous research on testosterone (T) and mating effort by examining whether relationship commitment and satisfaction explain variance in T beyond relationship status alone.

METHODS

Salivary testosterone and self-reported assessments of relationship commitment and satisfaction were assessed among 90 heterosexual men and women (age M = 23.57) in a cross-sectional community sample.

RESULTS

Relationship commitment was significantly related to T among men (P < 0.01), with increasing levels of commitment predicting lower T, even among paired men (P < 0.05). In contrast, relationship commitment was not related to women's T (P > 0.05). Controlling for relationship commitment, satisfaction did not predict T levels in men or women (P's > 0.18).

CONCLUSIONS

The association of increasing relationship commitment with reduced T levels in men confirms and extends prior research linking T with mating effort. Together with previous research, this study suggests that T does not vary with relationship commitment or quality in monogamous, heterosexual women.

The effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players

This study examined the effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players. Thirty male rugby players performed an upper-body power and lower-body strength (UPLS) and/or a lower-body power and upper-body strength (LPUS) workout using a crossover design (sprint vs. control). A 40-second upper-body or lower-body cycle sprint was performed before the UPLS and LPUS workouts, respectively, with the control sessions performed without the sprints. Bench throw (BT) power and box squat (BS) 1 repetition maximum (1RM) strength were assessed in the UPLS workout, and squat jump (SJ) power and bench press (BP) 1RM strength were assessed in the LPUS workout. Saliva was collected across each workout and assayed for testosterone (Sal-T) and cortisol (Sal-C). The cycle sprints improved BS (2.6 ± 1.2%) and BP (2.8 ± 1.0%) 1RM but did not affect BT and SJ power. The lower-body cycle sprint produced a favorable environment for the BS by elevating Sal-T concentrations. The upper-body cycle sprint had no hormonal effect, but the workout differences (%) in Sal-T (r = -0.59) and Sal-C (r = 0.42) concentrations correlated to the BP, along with the Sal-T/C ratio (r = -0.49 to -0.66). In conclusion, the cycle sprints improved the BP and BS 1RM strength of elite rugby players but not power output in the current format. The improvements noted may be explained, in part, by the changes in absolute or relative hormone concentrations. These findings have practical implications for prescribing warm-up and training exercises.

Stress hormone levels in saliva after shogi competition are modified by stress coping strategies

OBJECTIVE

Using shogi, a representative table game popular in Japan, to model a stress situation, we investigated the modulatory effects of player characteristics on changes in the levels of cortisol and testosterone in the saliva of the players.

METHODS

Saliva samples were collected at the following time-points: (1) 30 min after awakening on the day of the shogi convention; (2) immediately before the game; (3) immediately after the game; (4) 30 min after the end of game; (5) 30 min after awakening the following morning. The study cohort comprised 90 healthy male university students who were members of a shogi club, who were subsequently classified into either the emotional strategy (Em) or cognitive strategy (Co) group based on their scores on a Lazarus-type stress coping inventory.

RESULTS

Cortisol levels were significantly higher in the Em group than in the Co group the morning following the convention, and this difference was not affected by either outcome (victory or defeat) or perception (competitive or noncompetitive) of the match. A similar but non-significant trend was observed for testosterone levels.

CONCLUSION

Our findings suggest that the Em group had a greater capacity to manage the stress from a shogi convention than the Co group.

Children's internalizing symptoms: the role of interactions between cortisol and respiratory sinus arrhythmia

We examined interactions between children's physiological activity across two systems, the hypothalamic-pituitary-adrenal (HPA)-axis and the parasympathetic nervous system (PNS), as predictors of child-reported internalizing symptoms (depression, anxiety). HPA activity was indexed by baseline salivary cortisol, and PNS activity was indexed by baseline respiratory sinus arrhythmia (RSA). Study 1 consisted of 57 children (54% girls; M age=8.81 years ±.34), and Study 2 included 219 children (51% girls; M age=9.31 years ±.79). Cortisol interacted with RSA to explain unique variance in children's internalizing symptoms. Across the two studies, children with higher cortisol levels in conjunction with higher RSA levels tended to exhibit the lowest levels of depression and anxiety symptoms. Findings demonstrate that contemporaneous consideration of physiological activity across multiple systems can advance understanding of internalizing symptoms in children.

Steroid concentrations in plasma, whole blood and brain: effects of saline perfusion to remove blood contamination from brain

The brain and other organs locally synthesize steroids. Local synthesis is suggested when steroid levels are higher in tissue than in the circulation. However, measurement of both circulating and tissue steroid levels are subject to methodological considerations. For example, plasma samples are commonly used to estimate circulating steroid levels in whole blood, but steroid levels in plasma and whole blood could differ. In addition, tissue steroid measurements might be affected by blood contamination, which can be addressed experimentally by using saline perfusion to remove blood. In Study 1, we measured corticosterone and testosterone (T) levels in zebra finch (Taeniopygia guttata) plasma, whole blood, and red blood cells (RBC). We also compared corticosterone in plasma, whole blood, and RBC at baseline and after 60 min restraint stress. In Study 2, we quantified corticosterone, dehydroepiandrosterone (DHEA), T, and 17β-estradiol (E₂) levels in the brains of sham-perfused or saline-perfused subjects. In Study 1, corticosterone and T concentrations were highest in plasma, significantly lower in whole blood, and lowest in RBC. In Study 2, saline perfusion unexpectedly increased corticosterone levels in the rostral telencephalon but not other regions. In contrast, saline perfusion decreased DHEA levels in caudal telencephalon and diencephalon. Saline perfusion also increased E₂ levels in caudal telencephalon. In summary, when comparing local and systemic steroid levels, the inclusion of whole blood samples should prove useful. Moreover, blood contamination has little or no effect on measurement of brain steroid levels, suggesting that saline perfusion is not necessary prior to brain collection. Indeed, saline perfusion itself may elevate and lower steroid concentrations in a rapid, region-specific manner.

Salivary testosterone concentrations in pubertal ICSI boys compared with spontaneously conceived boys

BACKGROUND To date, no data exist about Leydig cell function of pubertal boys born after ICSI. To evaluate a potential risk of gonadal dysfunction in children born from fathers with compromised fertility, testicular function was assessed by the measurement of salivary testosterone. METHODS Morning salivary testosterone levels at the age of 14 years were compared between 58 ICSI teenagers who are part of the oldest ICSI cohort, and 62 boys born after spontaneous conception (SC). RESULTS Salivary testosterone levels were comparable between ICSI (113 ± 42 pg/ml) and SC (123 ± 56 pg/ml) teenagers at the age of 14 years. In the ICSI group, testosterone levels in boys from fathers with severe oligozoospermia were not different from concentrations in boys from fathers without severe oligozoospermia (115.5 ± 43 and 109 ± 41 pg/ml, respectively). CONCLUSIONS At the age of 14 years, pubertal ICSI boys show testosterone levels comparable to their peers born after SC. ICSI adolescents fathered from men with severely compromised spermatogenesis show testosterone levels comparable to those from fathers with normal spermatogenesis. This notwithstanding, further follow-up of ICSI teenagers into adulthood is mandatory to confirm a normal gonadal function.

Testosterone modifies the effect of APOE genotype on hippocampal volume in middle-aged men

BACKGROUND

The APOE epsilon4 allele is an established risk factor for Alzheimer disease (AD), yet findings are mixed for how early its effects are manifest. One reason for the mixed results could be the presence of interaction effects with other AD risk factors. Increasing evidence indicates that testosterone may play a significant role in the development of AD. The aim of the present study was to examine the potential interaction of testosterone and APOE genotype with respect to hippocampal volume in middle age.

METHODS

Participants were men from the Vietnam Era Twin Study of Aging (n = 375). The mean age was 55.9 years (range 51-59). Between-group comparisons were performed utilizing a hierarchical linear mixed model that adjusted for the nonindependence of twin data.

RESULTS

A significant interaction was observed between testosterone and APOE genotype (epsilon4-negative vs epsilon4-positive). Those with both low testosterone (> or =1 SD below the mean) and an epsilon4-positive status had the smallest hippocampal volumes, although comparisons with normal testosterone groups were not significant. However, individuals with low testosterone and epsilon4-negative status had significantly larger hippocampal volumes relative to all other groups. A main effect of APOE genotype on hippocampal volume was observed, but only when the APOE-by-testosterone interaction was present.

CONCLUSIONS

These findings demonstrate an interaction effect between testosterone and the APOE epsilon4 allele on hippocampal volume in middle-aged men, and they may suggest 2 low testosterone subgroups. Furthermore, these results allude to potential gene-gene interactions between APOE and either androgen receptor polymorphisms or genes associated with testosterone production.

Women's intercollegiate volleyball and tennis: effects of warm-up, competition, and practice on saliva levels of cortisol and testosterone

In virtually all sports, participants "warm-up" prior to formal competition. Women athletes from a highly ranked varsity college volleyball team and, in a second study, a highly ranked varsity college tennis team gave saliva samples before warm-up, at mid-warm-up (volleyball) or after warm-up (tennis), and immediately after intercollegiate competition. For volleyball and tennis, warm-up was associated with a substantial elevation in saliva levels of testosterone which was carried over through the period of actual competition. Cortisol levels were relatively unchanged during warm-up, but typically rose during competition. Thus, as women prepare for athletic competition by warming up, testosterone levels rise in apparent anticipation of the coming contest and then remain high through the period of play. In volleyball and tennis, after-practice testosterone level was significantly higher than before-practice level, and practice session increases in testosterone (but not cortisol) were positively correlated with increases in testosterone during intercollegiate competition. When practice and competitive play share as yet undetermined key elements, individual differences in this endocrine response to "competition" appear stable across practice and intercollegiate competition.

Certification testing as an acute naturalistic stressor for disaster dog handlers

USA Federal Disaster Canine Teams, consisting of a handler and a dog, are essential for locating survivors following a disaster. Certification, required by the Federal Emergency Management Agency Urban Search and Rescue organization, requires two successful mock searches. Confirmation of the certification testing process as an acute stressor might offer further opportunities to consider stress effects on handlers and dogs in a controlled environment. This study used a pretest-posttest design to evaluate relationships between salivary hormone concentrations (cortisol and testosterone) and subjective stress ratings in handlers and controls, handler assessments of stress in their dogs, and posttest temperature and pulse rate in dogs. Posttest, both subjective stress ratings and salivary cortisol concentration were higher in handlers than controls with both correlated to handlers' assessment of stress in their dogs. Handlers' posttest salivary cortisol concentration was associated with posttest dog pulse and temperature. Posttest cortisol concentration was lower in handlers who were successfully certified compared with those who failed, and was also lower in handlers whose primary occupation was "firefighter". Salivary testosterone concentrations increased from pretest to posttest in handlers but decreased in controls, and higher posttest handler testosterone concentration was negatively associated with posttest dog pulse rate. These findings confirm certification testing as an acute stressor, suggest a relationship between stress and performance moderated by occupation, and demonstrate an interaction between handler stress and dog physiological responses. This certification testing offers a controlled environment for targeted evaluation of effects of an acute naturalistic stressor on disaster dog handlers and dogs.

Caffeinated chewing gum increases repeated sprint performance and augments increases in testosterone in competitive cyclists

This investigation reports the effects of caffeinated chewing gum on fatigue and hormone response during repeated sprint performance with competitive cyclists. Nine male cyclists (mean ± SD, age 24 ± 7 years, VO(2max) 62.5 ± 5.4 mL kg(-1) min(-1)) completed four high-intensity experimental sessions, consisting of four sets of 30 s sprints (5 sprints each set). Caffeine (240 mg) or placebo was administered via chewing gum following the second set of each experimental session. Testosterone and cortisol concentrations were assayed in saliva samples collected at rest and after each set of sprints. Mean power output in the first 10 sprints relative to the last 10 sprints declined by 5.8 ± 4.0% in the placebo and 0.4 ± 7.7% in the caffeine trials, respectively. The reduced fatigue in the caffeine trials equated to a 5.4% (90% confidence limit ±3.6%, effect size 0.25; ±0.16) performance enhancement in favour of caffeine. Salivary testosterone increased rapidly from rest (~53%) and prior to treatments in all trials. Following caffeine treatment, testosterone increased by a further 12 ± 14% (ES 0.50; ± 0.56) relative to the placebo condition. In contrast, cortisol concentrations were not elevated until after the third exercise set; following the caffeine treatment cortisol was reduced by 21 ± 31% (ES -0.30; ± 0.34) relative to placebo. The acute ingestion of caffeine via chewing gum attenuated fatigue during repeated, high-intensity sprint exercise in competitive cyclists. Furthermore, the delayed fatigue was associated with substantially elevated testosterone concentrations and decreased cortisol in the caffeine trials.

17beta-Estradiol levels in male zebra finch brain: combining Palkovits punch and an ultrasensitive radioimmunoassay

Local aromatization of testosterone into 17beta-estradiol (E(2)) is often required for the physiological and behavioral actions of testosterone. In most vertebrates, aromatase is expressed in a few discrete brain regions. While many studies have measured brain aromatase mRNA or activity, very few studies have measured brain E(2) levels, particularly in discrete brain regions, because of technical challenges. Here, we used the Palkovits punch technique to isolate 13 discrete brain nuclei from adult male zebra finches. Steroids were extracted via solid phase extraction. E(2) was then measured with an ultrasensitive, specific and precise radioimmunoassay. Our protocol leads to high recovery of E(2) (84%) and effectively removes interfering brain lipids. E(2) levels were high in aromatase-rich regions such as caudal medial nidopallium and hippocampus. E(2) levels were intermediate in the medial preoptic area, ventromedial nucleus of the hypothalamus, lateral and medial magnocellular nuclei of anterior nidopallium, nucleus taeniae of the amygdala, and Area X. E(2) levels were largely non-detectable in the cerebellum, HVC, lateral nidopallium and optic lobes. Importantly, E(2) levels were significantly lower in plasma than in the caudal medial nidopallium. This protocol allows one to measure E(2) in discrete brain regions and potentially relate local E(2) concentrations to aromatase activity and behavior.

Testosterone Fluctuations in Young Men: The Difference between Interacting with like and Not-Like others

The current study investigated young men's testosterone level changes as a result of interacting with other men. Male participants ( n = 84) were led to believe that a group they would be interacting with was either similar to them or not similar. The interaction was then one of two types: the other group members were inclusive, or the others excluded the participant during the group interaction. Participants provided saliva samples before and after the interaction. Results suggest that interacting with highly similar men increases circulating testosterone whereas interacting with highly dissimilar men actually lowers testosterone. The nature of the interaction was less important than similarity. Considering that testosterone surges may relate to attempts to gain status within one's group, the results are interpreted as consistent with viewing hormonal changes as a mechanism to alter current behavioral propensities in ways that are likely to be most adaptive. Exploratory analyses suggest a methodologically interesting suppressor effect of the self-report items in predicting testosterone changes.

The development of gendered interests and personality qualities from middle childhood through adolescence: a biosocial analysis

This study charted the development of gendered personality qualities and activity interests from age 7 to age 19 in 364 first- and secondborn siblings from 185 White, middle/working-class families, assessed links between time in gendered social contexts (with mother, father, female peers, and male peers) and gender development, and tested whether changes in testosterone moderated links between time use and gender development. Multilevel models documented that patterns of change varied across dimensions of gender and by sex and birth order and that time in gendered social contexts was generally linked to development of more stereotypical qualities. Associations between time with mother and expressivity and time with father and instrumentality were stronger for youth with slower increases in testosterone.

Effects of aggressive encounters on plasma corticosteroid-binding globulin and its ligands in white-crowned sparrows

In birds, corticosteroid-binding globulin (CBG) binds corticosterone, progesterone and testosterone. The concentration of each ligand can alter the binding of the other ligands through competitive interactions. Thus, an increase in corticosterone or progesterone may displace testosterone bound to CBG, leading to an increase in bioactive free testosterone levels without affecting total testosterone levels in the circulation. Aggressive interactions increase plasma total testosterone levels in some birds but not in others. Here, we tested the hypothesis that aggressive encounters in the late breeding season would not increase total testosterone levels in plasma, but would alter CBG, total corticosterone or total progesterone levels in such a way as to modify the number of available binding sites and therefore occupancy by testosterone. A marked decrease in CBG occupancy by testosterone would indirectly suggest an increase in free testosterone levels in plasma. Wild male white-crowned sparrows were exposed to a simulated territorial intrusion (STI) or control for 30 min. Subjects were then caught and bled. We measured CBG using a ligand-binding assay and corticosterone, progesterone and testosterone using highly sensitive radioimmunoassays. STI significantly increased aggressive behaviors but did not affect plasma total testosterone levels. STI significantly increased plasma CBG and total corticosterone levels and decreased plasma total progesterone levels. We predict that CBG occupancy by corticosterone will increase slightly following an aggressive encounter. However, this small change is unlikely to increase free testosterone levels, because of the large number of seemingly unoccupied CBG binding sites in these subjects.

Stressor paradigms in developmental studies: what does and does not work to produce mean increases in salivary cortisol

The stress response system is comprised of an intricate interconnected network that includes the hypothalamic-pituitary-adrenocortical (HPA) axis. The HPA axis maintains the organism's capacity to respond to acute and prolonged stressors and is a focus of research on the sequelae of stress. Human studies of the HPA system have been facilitated enormously by the development of salivary assays which measure cortisol, the steroid end-product of the HPA axis. The use of salivary cortisol is prevalent in child development stress research. However, in order to measure children's acute cortisol reactivity to circumscribed stressors, researchers must put children in stressful situations which produce elevated levels of cortisol. Unfortunately, many studies on the cortisol stress response in children use paradigms that fail to produce mean elevations in cortisol. This paper reviews stressor paradigms used with infants, children, and adolescents to guide researchers in selecting effective stressor tasks. A number of different types of stressor paradigms were examined, including: public speaking, negative emotion, relationship disruption/threatening, novelty, handling, and mild pain paradigms. With development, marked changes are evident in the effectiveness of the same stressor paradigm to provoke elevations in cortisol. Several factors appear to be critical in determining whether a stressor paradigm is successful, including the availability of coping resources and the extent to which, in older children, the task threatens the social self. A consideration of these issues is needed to promote the implementation of more effective stressor paradigms in human developmental psychoendocrine research.

Oral contraceptives decrease saliva testosterone but do not affect the rise in testosterone associated with athletic competition

Women athletes from intercollegiate soccer, volleyball, and softball teams, and women skaters from a team competing in an amateur roller derby league, contributed saliva samples before warm-up and immediately after the completion of one or more sanctioned competitions. Women using oral contraceptives (OCs, n=29) had a significantly lower mean level of saliva testosterone (T) than non-users (n=51). Thus, OCs contribute predictable variation to individual differences in saliva T, and OC use is likely to contribute to individual differences in measures of psychological processes and/or behavior which are causally related to individual differences in circulating testosterone. Most of the women (n=68) played during one or more of the competitions for which they contributed saliva samples. Whether for soccer, volleyball, softball, or roller derby, competition was associated with a robust increase in saliva T. Although OC users had significantly lower saliva T levels than non-users before and after-competition, both users and non-users showed virtually the same increase in saliva T over the course of competition. While the most proximal cause of this increase is not known, it is probably not the result of an increase in gonadotropin (GTH) secretion since an increase in GTH secretion would presumably be prevented by OC use.

Choosing the types of biological sample to collect in longitudinal birth cohort studies

There are a variety of biological samples that can be collected from participants in longitudinal studies. Here we outline those that are particularly useful in longitudinal birth cohort studies starting in pregnancy, and discuss their advantages and disadvantages.

Relationship between levels of testosterone and cortisol in saliva and aggressive behaviors of adolescents

OBJECTIVE

To explore the endocrinal factors which influence the aggressive behavior of adolescents.

METHODS

The levels of cortisol (CORT), testosterone (T), prolactin (PRL), and growth hormone (GH) in saliva from 20 aggressive students and 20 non-aggressive control students were measured by radioimmunoassay (RIA). The students were matched for their gender, age, grade, stage of pubertal development, and economic status of their families.

RESULTS

The salivary T levels were 22.20 +/- 14.50 pg/mL and 19.54 +/- 12.52 pg/mL in aggressive male and female students, 13.20 +/- 6.85 pg/mL and 5.24 +/- 3.03 pg/mL in non-aggressive male and female students (P < 0.05). The male aggressive students had a lower level of CORT in saliva than non-aggressive male students (P < 0.05). There were no significant differences in the salivary levels of PRL or GH between the aggressive and non-aggressive groups. Correlation analysis revealed a negative relationship in male students between the salivary CORT levels and the aggression factor scores of the child behavior checklist (CBCL). In addition, the data also showed a positive relationship between the salivary T levels and the aggression factor scores of CBCL in female students. Multiple linear regression analysis showed that the salivary CORT level was an independent predictive factor for aggressive behaviors in adolescent boys. The higher the CORT level, the less aggressive the boys were.

CONCLUSION

CORT and T levels may play a certain role in adolescent aggressive behaviors.

Salivary gonadal and adrenal hormone differences in boys and girls with and without disruptive behavior disorders: Contextual variants

Hormone differences by psychopathology group and gender may have implications for understanding disruptive behavior disorders (DBDs) and complexities of treatment outcomes. Current theoretical models emphasize contextual differences as moderators of hormone-behavior relations. This baseline report examined: (a) hormone differences in youth with and without DBD, and (b) contextual factors as moderators of behavior problems and hormones. 180 children and adolescents were enrolled (141 boys, mean 9.0+/-1.7 years). DBD participants met criteria for conduct disorder (CD) and/or oppositional defiant disorder (ODD) (n=111); 69 were recruited as healthy comparisons (HC). Saliva was collected for testosterone, cortisol, dehydroepiandrosterone and androstenedione. DBD youth had significantly higher androstenedione than the HC group. There was a group by gender interaction for basal cortisol mean with DBD boys and HC girls having lower cortisol. Moderating effects of contextual variables (e.g., family functioning, delinquent peers) were noted for cortisol and adrenal androgens. Findings argue for considering hormones as an influence on DBD beyond simple direct one-to-one associations.

Rationale and methodological options for assessing infectious disease and related measures in social science surveys

Infectious disease is an important, but often overlooked, component of population health in high-income nations. Common, everyday infections exact significant costs, including school and work absenteeism, reduced productivity, and substantial health care expenditures. Infectious disease also shapes trajectories of biological risk and health and may be causally linked to chronic disease risk later in life. The size, diversity, and representativeness of samples typically employed in survey-based studies of health present exceptional opportunities for advancing scientific knowledge on the social and economic determinants of infectious disease in childhood and adulthood and to investigate the long-term consequences of infectious disease for well-being and attainment across multiple domains. A wide range of interview-based, anthropometric, and biomarker measurement options are currently available for assessing infectious exposures, inflammation, and immune function in nonclinical settings. These methods afford opportunities for innovative, transdisciplinary research on the causes and consequences of infectious disease across the life course that can address questions of interest to social, life, and biomedical scientists.