A critical evaluation of salivary testosterone as a method for the assessment of serum testosterone

The utility of salivary testosterone and cortisol concentration measures for assessing the stress responses of junior athletes during a sporting competition

BACKGROUND

This study examined the utility of salivary testosterone (T) and cortisol (C) concentration measures for assessing the acute stress responses of junior athletes during a sporting competition.

METHODS

Paired capillary blood and saliva samples were taken from 71 junior athletes (45 males, 26 females) before and after a simulated Olympic weightlifting competition. The concentration measures of salivary T and C were referenced against blood total T (TT) and C (TC) concentrations. All hormones were tested by immunoassay.

RESULTS

The competition promoted an increase in the blood TT concentrations of the male (10.1%±18.7%) and female (12.9%±19.9%) athletes (P<.05), with TC also rising in females (37.5%±69%) and tending to increase in males (23.2%±56.1%). No significant changes in salivary T or C were identified. Locally-weighted regression revealed that salivary T was strongly related to blood TT in males (r² =.84), but not females (r² =-.15), whereas salivary C was moderately related to blood TC in both sexes (r² =.43, r² =.48), respectively.

CONCLUSIONS

A short, high-intensity competition promoted a predictable stress-induced rise in blood TT and TC concentrations. We observed no hormonal stress responses in saliva under the current format, which could be explained by individual variability and blood-saliva differences in hormone kinetics. Still, the salivary T and C measures did show a moderate to strong ability to track individual blood TT (males only) and TC (both sexes) concentrations in a young athletic cohort across a broad physiological range. Recommendations for researchers and practitioners are presented.

Testosterone in human studies: Modest associations between plasma and salivary measurements

Testosterone is involved in many processes like aggression and mood disorders. As it may easily diffuse from blood into saliva, salivary testosterone is thought to reflect plasma free testosterone level. If so, it would provide a welcome noninvasive and less stressful alternative to blood sampling. Past research did not reveal consensus regarding the strength of the association, but sample sizes were small. This study aimed to analyse the association in a large cohort. In total, 2,048 participants (age range 18-65 years; 696 males and 1,352 females) were included and saliva (using cotton Salivettes) and plasma were collected for testosterone measurements. Levels were determined by enzyme-linked immunosorbent assay and radioimmunoassay respectively. Free testosterone was calculated by the Vermeulen algorithm. Associations were determined using linear regression analyses. Plasma total and free testosterone showed a significant association with salivary testosterone in men (adjusted β = .09, p = .01; and β = .15, p < .001, respectively) and in women (adjusted β = .08, p = .004; and crude β = .09, p = .002 respectively). The modest associations indicate that there are many influencing factors of both technical and biological origin.

Effects of Testosterone Therapy on Cognitive Function in Aging: A Systematic Review

Endogenous testosterone in the aging man has been scrutinized extensively in regard to its effects on performance in many cognitive domains, especially verbal fluency, visuospatial and visuoperceptual abilities, memory, and executive function. Studies of testosterone supplementation have sought to identify potential cognitive improvements in men with and without baseline cognitive impairment, and have had a wide range of results. The variability in outcomes is likely related, in part, to the lack of consensus on methods for testosterone measurement and supplementation and, in part, to the disparate measures of cognitive function used in randomized controlled studies. Despite the limitations imposed by such inconsistent methods, promising associations have been found between cognition and testosterone supplementation in both eugonadal men and men with low testosterone levels, with and without baseline cognitive dysfunction. This systematic review highlights the cognitive measures used in and the outcomes of existing studies of testosterone and cognition in aging men. The review suggests that larger studies and a more standardized approach to assessment will be needed before we can fully understand and realize sustained benefits from testosterone supplementation in the elderly male population, particularly given the substantial increase in testosterone supplementation in clinical practice.

Salivary estradiol as a surrogate marker for serum estradiol in assisted reproduction treatment

INTRODUCTION

Controlled ovarian hyper-stimulation for in vitro fertilization or intra cytoplasmatic sperm injection necessitates close monitoring using ultrasound and estradiol measurements. Monitoring is also important to prevent or limit the severity of ovarian hyper stimulation syndrome, an iatrogenic and potentially life-threatening complication. Self-operated endovaginal telemonitoring has been shown to offer an attractive and less costly alternative to classic consultation and saliva estradiol measurements could be a stress-free and practical alternative to serial blood determinations. Objectives were to evaluate whether saliva can be a surrogate marker for serum estradiol and its potential applicability in assisted reproduction treatment monitoring.

MATERIAL AND METHODS

Serial blood and saliva samples were collected from 31 patients undergoing ovarian hyper-stimulation. All patients were followed-up using in-house serial vaginal sonograms and immunoassay serum estradiol measurements. Afterwards estradiol was determined in saliva and serum by LC-MS/MS. For a subset equilibrium dialysis and measurement of free serum estradiol was performed.

RESULTS

About 1% of estradiol is present in serum in its free, unbound, form. Salivary estradiol correlates well to both serum free estradiol and serum total estradiol (r=0.80). The concentration of salivary estradiol corresponds to the unbound concentration in serum. The dynamics observed in serum monitoring during treatment are closely mimicked in saliva. ROC analysis on the current limited dataset suggested a saliva cut-off of 22pg/mL (81pmol/L) could help predict risk for OHSS.

CONCLUSIONS

Salivary E2 can be considered a surrogate marker for free serum estradiol and total serum estradiol in assisted reproduction treatment. Additionally there might be a role as a prediction marker for OHSS although this finding has to be validated in larger datasets.

Parallel diurnal fluctuation of testosterone, androstenedione, dehydroepiandrosterone and 17OHprogesterone as assessed in serum and saliva: validation of a novel liquid chromatography-tandem mass spectrometry method for salivary steroid profiling

Background:

Salivary androgen testing represents a valuable source of biological information. However, the proper measurement of such low levels is challenging for direct immunoassays, lacking adequate accuracy. In the last few years, many conflicting findings reporting low correlation with the serum counterparts have hampered the clinical application of salivary androgen testing. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) makes it possible to overcome previous analytical limits, providing new insights in endocrinology practice.

Methods:

Salivary testosterone (T), androstenedione (A), dehydroepiandrosterone (DHEA) and 17OHprogesterone (17OHP) were extracted from 500µL of saliva, separated in 9.5 min LC-gradient and detected by positive electrospray ionization – multiple reaction monitoring. The diurnal variation of salivary and serum androgens was described by a four paired collection protocol (8 am, 12 am, 4 pm and 8 pm) in 19 healthy subjects.

Results:

The assay allowed the quantitation of T, A, DHEA and 17OHP down to 3.40, 6.81, 271.0 and 23.7 pmol/L, respectively, with accuracy between 83.0 and 106.1% for all analytes. A parallel diurnal rhythm in saliva and serum was observed for all androgens, with values decreasing from the morning to the evening time points. Salivary androgen levels revealed a high linear correlation with serum counterparts in both sexes (T: R>0.85; A: R>0.90; DHEA: R>0.73 and 17OHP: R>0.89; p<0.0001 for all).

Conclusions:

Our LC-MS/MS method allowed a sensitive evaluation of androgen salivary levels and represents an optimal technique to explore the relevance of a comprehensive androgen profile as measured in saliva for the study of androgen secretion modulation and activity in physiologic and pathologic states.

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.

Effects of sex hormone-binding globulin (SHBG) on androgen bioactivity in vitro

Biochemical assessments of androgen status (hyper- or hypoandrogenism) are usually based on serum testosterone concentrations. According to the free hormone hypothesis, sex hormone-binding globulin (SHBG) determines free and bioavailable testosterone concentrations. Previous studies have suggested that in vitro androgen bioassay results may also be influenced by SHBG and correlate with free or bioavailable testosterone concentrations. To test this hypothesis, we established a stable HEK293 cell line with high expression of the human androgen receptor (AR) and a luciferase reporter downstream of a classical androgen response element. Importantly, we demonstrate that bioassay results are sensitive to dilution effects which increase apparent bioactivity in an SHBG-dependent manner. We therefore adopted a method using undiluted serum, which reduced cell proliferation but did not significantly affect the luciferase signal, cell viability or cytotoxicity. To correct for serum matrix effects, we applied signal correction based on internal controls with AR agonists or antagonists. Using this method, we provide direct evidence that in vitro androgen bioactivity reflects the inhibitory effects of SHBG, and correlates with free or bioavailable testosterone concentrations in adult hypogonadal men receiving androgen replacement therapy. In men receiving anti-androgens, serum bioactivity decreased tenfold while serum testosterone concentrations decreased only four-fold. Further pilot results in prostate cancer patients showed that androgen synthesis inhibitors result in more complete inhibition of androgen bioactivity than gonadorelin-based androgen deprivation therapy, even in patients whose testosterone concentrations were undetectable by mass spectrometry. We conclude that in vitro androgen reporter bioassays are useful tools to study how androgen bioactivity in serum is determined by androgens, anti-androgens as well as SHBG, provided that dilution and matrix effects are accounted for.

The effect of sex and time of day on testosterone concentrations in equine saliva and serum

In terms of exercise, testosterone is important for the growth and maintenance of skeletal muscle mass. Sampling saliva could be a non-invasive alternative to blood sampling for the quantification of testosterone levels in horses. The objective of this study was to compare testosterone concentrations in saliva and serum (sampled simultaneously) from horses of different sexes and at different times throughout the day. A total of 67 warmblood riding horses (21 geldings, 22 mares and 24 stallions) were included in the study. Saliva and blood samples were collected in the morning (06:00-08:00), at midday (11:00-13:00) and in the evening (17:00-19:00). The results demonstrated a weak correlation between saliva and serum testosterone concentrations (rs=0.25, P=0.04). Stallions had higher serum testosterone concentrations than mares and geldings (P<0.001), but there was no significant effect of sex on salivary testosterone concentrations. The time of day did not affect the concentration of testosterone in either saliva or serum. In conclusion, our results indicate that saliva samples cannot be recommended for measuring testosterone levels in horses. However, further research is needed to identify the disturbing factors.

Salivary Testosterone Levels and Health Status in Men and Women in the British General Population: Findings from the Third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

CONTEXT

Salivary T (Sal-T) measurement by liquid chromatography-tandem mass spectroscopy resents the opportunity to examine health correlates of Sal-T in a large-scale population survey.

OBJECTIVE

This study sought to examine associations between Sal-T and health-related factors in men and women age 18-74 years.

DESIGN AND SETTING

Morning saliva samples were obtained from participants in a cross-sectional probability-sample survey of the general British population (Natsal-3). Self-reported health and lifestyle questions were administered as part of a wider sexual health interview.

PARTICIPANTS

Study participants included 1599 men and 2123 women.

METHODS

Sal-T was measured using liquid chromatography-tandem mass spectroscopy. Linear regression was used to examine associations between health factors and mean Sal-T.

RESULTS

In men, mean Sal-T was associated with a range of health factors after age adjustment, and showed a strong independent negative association with body mass index (BMI) in multivariable analysis. Men reporting cardiovascular disease or currently taking medication for depression had lower age-adjusted Sal-T, although there was no association with cardiovascular disease after adjustment for BMI. The decline in Sal-T with increasing age remained after adjustment for health-related factors. In women, Sal-T declined with increasing age; however, there were no age-independent associations with health-related factors or specific heath conditions with the exception of higher Sal-T in smokers.

CONCLUSIONS

Sal-T levels were associated, independently of age, with a range of self-reported health markers, particularly BMI, in men but not women. The findings support the view that there is an age-related decline in Sal-T in men and women, which cannot be explained by an increase in ill health. Our results demonstrate the potential of Sal-T as a convenient measure of tissue androgen exposure for population research.

Sex hormone-binding globulin regulation of androgen bioactivity in vivo: validation of the free hormone hypothesis

Sex hormone-binding globulin (SHBG) is the high-affinity binding protein for androgens and estrogens. According to the free hormone hypothesis, SHBG modulates the bioactivity of sex steroids by limiting their diffusion into target tissues. Still, the in vivo physiological role of circulating SHBG remains unclear, especially since mice and rats lack circulating SHBG post-natally. To test the free hormone hypothesis in vivo, we examined total and free sex steroid concentrations and bioactivity on target organs in mice expressing a human SHBG transgene. SHBG increased total androgen and estrogen concentrations via hypothalamic-pituitary feedback regulation and prolonged ligand half-life. Despite markedly raised total sex steroid concentrations, free testosterone was unaffected while sex steroid bioactivity on male and female reproductive organs was attenuated. This occurred via a ligand-dependent, genotype-independent mechanism according to in vitro seminal vesicle organ cultures. These results provide compelling support for the determination of free or bioavailable sex steroid concentrations in medicine, and clarify important comparative differences between translational mouse models and human endocrinology.

Varicocele: the origin of benign prostatic hypertrophy? Testosterone dosages in the periprostatic plexus

OBJECTIVES

In 2008, Gat et al. wrote the hypothesis that benign prostatic hypertrophy (BPH) was caused by reflux from high free testosterone containing blood from varicocele. The purpose of this study is to measure testosterone at the prostatic veins in patients operated for large BPH, confirming Gat's theory.

MATERIAL AND METHODS

In 13 patients, operated by Millin technique, the periprostatic plexus was punctured in 45° tilted position in order to the measure total and free testosterone and dihydrotestosterone. Brachial blood was taken simultaneously for similar measurements. Seven patients had a clinical varicocele.

RESULTS

High testosterone levels, in comparison with the brachial blood, were detected in only two patients. Dihydrotestosterone was at least doubled in all cases, demonstrating that the puncture was done in prostatic drainage area.

CONCLUSION

Gat's theory, concerning the role of varicocele in the origin of BPH, could not be confirmed in this study. Technical limitations can be responsible for this.

Effects of Hydrocortisone on the Regulation of Blood Pressure: Results From a Randomized Controlled Trial

CONTEXT

Cardiovascular risk is increased in patients with secondary adrenal insufficiency, which may be ascribed to an unfavorable metabolic profile consequent to a relatively high hydrocortisone replacement dose.

OBJECTIVE

We determined the effects of a higher versus a lower glucocorticoid replacement dose on blood pressure (BP), the renin-angiotensin-aldosterone system, 11β-hydroxysteroid dehydrogenase enzyme activity and circulating (nor)metanephrines.

DESIGN, SETTING, AND PATIENTS

Forty-seven patients with secondary adrenal insufficiency from the University Medical Center Groningen participated in this randomized double-blind crossover study.

INTERVENTIONS

Patients randomly received 0.2-0.3 mg hydrocortisone/kg body weight followed by 0.4-0.6 mg hydrocortisone/kg body weight, or vice versa, each during 10 weeks.

MAIN OUTCOME MEASURE(S)

BP and regulating hormones were measured.

RESULTS

The higher hydrocortisone dose resulted in an increase in systolic BP of 5 (12) mm Hg (P = .011), diastolic BP of 2 (9) mm Hg (P = .050), and a median [interquartile range] drop in plasma potassium of -0.1 [-0.3; 0.1] nmol/liter (P = .048). The higher hydrocortisone dose led to decreases in serum aldosterone of -28 [-101; 9] pmol/liter (P = .020) and plasma renin of -1.3 [-4.5; 1.2 ] pg/mL (P = .051), and increased the ratio of plasma and urinary cortisol to cortisone (including their metabolites) (P < .001 for all). Furthermore, on the higher dose, plasma and urinary normetanephrine decreased by -0.101 [-0.242; 0.029] nmol/liter (P < .001) and -1.48 [-4.06; 0.29] μmol/mol creatinine (P < .001) respectively.

CONCLUSIONS

A higher dose of hydrocortisone increased systolic and diastolic BP and was accompanied by changes in the renin-angiotensin-aldosterone system, 11β-hydroxysteroid dehydrogenase enzyme activity, and circulating normetanephrine. This demonstrates that hydrocortisone dose even within the physiological range affects several pathways involved in BP regulation.

Testosterone, cortisol, and human competition

Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C - this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research.

Mass spectrometric quantification of salivary metanephrines-A study in healthy subjects

BACKGROUND

Determination of metanephrine (MN), normetanephrine (NMN), and 3-methoxytyramine (3-MT) in saliva may offer potential diagnostic advantages in diagnosing pheochromocytoma.

METHODS

In this preliminary study, we determined metanephrine concentrations in saliva of healthy subjects and the relationship with simultaneously measured plasma metanephrines. We also studied the possible influence of pre-analytical conditions such as a collection device, awakening, posture, and eating on the salivary metanephrine levels.

RESULTS

Eleven healthy subjects were included. Fasting blood and saliva samples were collected in seated position and after 30min of horizontal rest. Plasma and salivary MN, NMN, and 3-MT concentrations were determined using a high-performance liquid chromatography tandem mass spectrometric technique (LC-MS/MS) with automated solid phase extraction sample preparation. Metanephrines were detectable in saliva from all participants both in seated and supine position. No significant correlations were observed between the MN, NMN, and 3-MT concentrations in saliva and plasma in seated or supine position. Furthermore, there was no difference between MN, NMN, and 3-MT samples collected with or without a collection device.

CONCLUSION

Metanephrines can be detected in saliva with LC-MS/MS with sufficient sensitivity and precision. Our findings warrant evaluation of salivary metanephrine measurement as a novel laboratory tool in the work-up of patients suspected of having a pheochromocytoma.

Salivary markers of kidney function - Potentials and limitations

Saliva can be collected non-invasively, repeatedly and without trained personnel. It is a promising diagnostic body fluid with clinical use in endocrinology and dentistry. For decades, it is known that saliva contains also urea, creatinine and other markers of renal function. Clinical studies have shown that the salivary concentrations of these markers could be useful for the assessment of kidney function without the need of blood collection. This article summarizes the clinical and experimental data on the use of saliva as a diagnostic fluid in nephrology and points out the advantages, pitfalls, technical requirements and future perspective for the use of saliva as a novel potential diagnostic biofluid.

Poor levels of agreement between serum and saliva testosterone measurement following exercise training in aging men

Testosterone (T) is a biologically important androgen that demonstrates a widely-known natural decline with advancing age. The use of salivary T (sal-T), as a determinant of systemic T, has shown promising results in recent years. However, the strength of the salivary-serum T relationship may be affected by measurement method and binding capacity with salivary proteins. The potential influence exercise may impact on this relationship is unstudied in aging men. Therefore, the aim of the present investigation was to examine the relationship of the delta change (Δ) in sal-T with Δserum T following six weeks exercise training. Fifteen sedentary (SED) males (aged 60.4 ± 5.0 years of age) and 20 lifelong exercising (LE) males (60.4 ± 4.7 years of age) were participated. Pearson's correlation coefficient revealed sal-T did not correlate with total testosterone (TT), sex hormone binding globulin (SHBG), bioactive T (bio-T), or free T (free-T) at week 0 or week 6. Δsal-T did not correlate with ΔTT, ΔSHBG, Δbio-T or Δfree-T (r = 0.271, p = 0.180; r = 0.197, p = 0.335; r = 0.258, p = 0.205; and r = 0.257, p = 0.205, respectively). In conclusion, poor levels of agreement existed between saliva and serum measurements of T in response to exercise amongst aging men.