Testosterone in human saliva

Promising applications of human-derived saliva biomarker testing in clinical diagnostics

Saliva testing is a vital method for clinical applications, for its noninvasive features, richness in substances, and the huge amount. Due to its direct anatomical connection with oral, digestive, and endocrine systems, clinical usage of saliva testing for these diseases is promising. Furthermore, for other diseases that seeming to have no correlations with saliva, such as neurodegenerative diseases and psychological diseases, researchers also reckon saliva informative. Tremendous papers are being produced in this field. Updated summaries of recent literature give newcomers a shortcut to have a grasp of this topic. Here, we focused on recent research about saliva biomarkers that are derived from humans, not from other organisms. The review mostly addresses the proceedings from 2016 to 2022, to shed light on the promising usage of saliva testing in clinical diagnostics. We recap the recent advances following the category of different types of biomarkers, such as intracellular DNA, RNA, proteins and intercellular exosomes, cell-free DNA, to give a comprehensive impression of saliva biomarker testing.

Saliva proteomic analysis reveals possible biomarkers of renal cell carcinoma

Early diagnosis is a key to improve the prognosis of renal cell carcinoma (RCC); however, reliable RCC biomarkers are lacking in clinical practice. In this study, we used isobaric tags for relative and absolute quantification-based mass spectrometry to identify salivary proteins as biomarkers for the diagnosis of RCC. The objective of this study is to discover biomarkers from saliva by utilizing high-throughput quantitative proteomics approaches. Saliva proteins from 124 RCC patients and healthy individuals were identified and quantified. RCC putative biomarkers were verified by real-time polymerase chain reaction or enzyme-linked immunosorbent assay in a prevalidation sample set. Seventy-one differentially expressed salivary proteins were identified. Serotransferrin, haptoglobin, KRT9, and S100A9, which in previous studies were found to be most closely related to cancers, were selected as putative RCC biomarkers. Haptoglobin and S100A9 were significantly elevated in RCC compared with healthy control samples, although the expression of serotransferrin and KRT9 did not differ between the groups. Furthermore, receiver operating characteristic curves with a cut-off value of 75.49 ng/mL for S100A9 revealed a sensitivity of 87.10% and a specificity of 91.94% for discriminating RCC patients from healthy individuals. Salivary haptoglobin differentiated RCC patients from healthy controls with a sensitivity of 85.48% and specificity of 80.65% (cut-off value 43.02 µg/mL). These results provide experimental evidence to support S100A9 and haptoglobin as potential novel, noninvasive biomarkers for the diagnosis of RCC.

Children's Body Odors: Hints to the Development Status

Mothers can recognize their own children by body odor. Besides signaling familiarity, children's body odors may provide other information relevant to maternal caregiving behavior, such as the child's developmental status. Thus, we explored whether mothers are able to classify body odors on pre- vs. postpubertal status above chance levels. In total, 164 mothers were presented with body odor samples of their own and four unfamiliar, sex-matched children who varied in age (range 0-18 years). Pubertal status was measured by (a) determining the child's steroid hormone level and (b) parental assessment of the child's developmental stage using the Pubertal Development Scale. Mothers classified developmental status with an accuracy of about 64%. Maternal assessments were biased toward pre-puberty. Classification was predicted by perceptual evaluation of the body odor (i.e. intensity and pleasantness) and by the child's developmental stage, but not by hormones. In specific, mothers with pubertal-aged children classified body odors using the child's developmental status, whereas mothers with younger children only classified body odors using perceptual information (i.e. intensity and pleasantness). Our data suggests that body odors convey developmental cues, but how this developmental information is manifested in body odor remains unclear.

Exercise-induced responses in salivary testosterone, cortisol, and their ratios in men: a meta-analysis

BACKGROUND

Testosterone, cortisol and their ratios may be indicators of anabolic status, but technical issues surrounding blood sampling has limited wider application. The advent of salivary testosterone (sal-T) analysis simplified sample acquisition, resulting in a subsequent rapid increase in the number of published research articles.

OBJECTIVE

The objective of this study was to undertake a meta-analysis to determine the effect of acute exercise bouts on post exercise sal-T and salivary cortisol (sal-C) concentrations and their ratio (sal-T:C).

DATA SOURCES

Relevant databases such as PubMed, Web of Science, Science Direct and SPORTDiscus were searched up to and including 31 December 2013 for the term 'saliva AND testosterone AND exercise'.

STUDY SELECTION

Studies (n = 21) selected from the 933 identified included randomised controlled trials (RCTs; n = 2), uncontrolled trials (UCTs; n = 18) and control trials (CTs; n = 1), all of which had an exercise component characterised as either aerobic, resistance or power training, each with acute sal-T and sal-C measurement obtained within 30 min of exercise bout completion.

STUDY APPRAISAL AND SYNTHESIS METHODS

A meta-analysis was conducted on change in sal-T, sal-C and the sal-T:C ratio following exercise using standard difference in means (SDM) and a random effects model.

RESULTS

For aerobic, resistance and power exercise, the overall SDMs for sal-T were 0.891, 1.061 and 0.509, respectively; for sal-C, the SDMs were 3.041, 0.773 and 1.200, respectively. For sal-T:C, the SDMs were -2.014, 0.027 and -0.968, respectively. RCTs, UCTs and CTs were separated by subgroup analysis. There were significant differences in overall weighted SDM values for sal-T between RCTs, UCTs and CTs within exercise modes. When examining aerobic exercise interventions, a quantitative interaction of study design was observed. RCTs resulted in a greater SDM than UCTs (1.337 vs. 0.446). Power interventions displayed a qualitative interaction with study design. UCTs where baseline measures were obtained 24 h before exercise had an SDM of -1.128, whereas UCTs where baseline was determined immediately prior to exercise had an SDM of 0.486. The single CT trial had an SDM of 2.260. Resistance exercise interventions were primarily UCTs; however, an observed influence of baseline sampling time whereby immediately pre- and 24 h pre-exercise resulted in differing SDMs. The sole resistance exercise RCTs resulted in the greatest SDM (2.500).

CONCLUSION

The current body of evidence regarding acute responses of sal-T to exercise is weak. This meta-analysis identifies varying exercise-dependent effect sizes. Each appear to be greatly influenced by study design and sample timing. There is a need for more RCTs and a standardised methodology for the measurement of salivary hormones in order to better determine the effect of exercise modality.

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.

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.

Unstimulated whole saliva creatine phosphokinase in acute myocardial infarction

OBJECTIVE

Accurate and rapid diagnosis of acute myocardial infarction (MI) is of major medical and economic importance. The objective of this study was to identify unstimulated whole saliva creatine phosphokinase (CPK) in patients with acute MI.

SUBJECTS AND METHODS

A case-control study was carried out in 30 normal healthy individuals and 30 patients with acute MI were hospitalized in CCU of Kamkar hospital, Qom, Iran. CPK levels were assayed in serum and unstimulated whole saliva at the first and the second days of acute MI by IFCC method. Statistical analysis of the Student's t-test and Pearson correlation coefficient was performed.

RESULTS

The mean saliva and serum levels at both the first and the second days of acute MI were significantly higher in patients with acute MI compared with healthy individuals. They were significantly greater in the first day than in the second day. Saliva CPK concentration correlated significantly with serum CPK level in the first day (r = 0.442, P < 0.01) and in the second day of acute MI (r = 0.268, P < 0.01).

CONCLUSION

Results suggest that salivary CPK can be used as an alternative to serum CPK for diagnosis and monitoring of myocardial infarction.

Salivary testosterone: a reliable approach to the diagnosis of male hypogonadism

OBJECTIVE

This study was to demonstrate that Sal-T is a reliable biomarker of androgen status in the diagnosis of male hypogonadism.

DESIGN

In order to validate the salivary testosterone assay (Sal-T), its reproducibility, the agreement with serum free testosterone levels (Free-T), the correlation with other circulating androgen markers (bioavailable testosterone, total testosterone) and cut-off values were defined.

PATIENTS AND METHODS

We studied 52 eugonadic (E) and 20 hypogonadic (Hy) men. Sal-T was assayed using an adapted radioimmunoassay for serum testosterone. Sal-T concentrations were compared in nine cases before and after citric acid stimulation of salivary flow rate. Free-T and bioavailable testosterone (Bio-T) were calculated by Vermeulen equation and SHBG were determined by binding assay.

RESULTS

Sal-T did not depend on salivary flow rate and morning samples from 07.00 h to 09.00 h were stable. Agreement between Sal-T and Free-T measurements was confirmed in all subjects. Sal-T levels correlated positively with all circulating androgens, showing the best correlation with Free-T in E (r = 0.92) as well as in Hy (r = 0.97). A cut-off value of Sal-T < or = 0.195 nm showed 100% sensibility and specificity to rule out hypogonadism.

CONCLUSIONS

Our data showed that Sal-T is a reliable marker of testosterone bioavailability. The results support the inclusion of this biomarker as a noninvasive approach in the diagnosis of male androgen deficiency.

Validation of salivary testosterone as a screening test for male hypogonadism

BACKGROUND

Saliva collection is an easy, non-invasive method to measure hormones.

METHODS

Two studies were performed. In the first, a convenience sample of 1,454 males who had submitted saliva for salivary testosterone measurements were studied. In the second study, we intensively studied symptoms and measurements of total testosterone, free testosterone symptoms and measurements of total testosterone, free testosterone and bioavailable testosterone in relationship to salivary testosterone in 127 men. A secondary endpoint was to examine the relationship of salivary testosterone to hypogonadal symptoms in the ADAM and AMS questionnaires.

RESULTS

In the first study, we have shown that salivary testosterone, measured in 1,454 males aged 20 to 89 years, declines by 47% over the lifespan. In the second study, salivary testosterone was strongly correlated with bioavailable testosterone (p < 0.000001) calculated free testosterone (p < 0.00001) and total testosterone (p < 0.002). Salivary testosterone was significantly related to hypogonadal symptoms on the St. Louis University ADAM questionnaire and the Aging Male Survey.

CONCLUSIONS

These studies support the use of salivary testosterone as an acceptable assay for screening for hypogonadism. Salivary testosterone is not a better assay than other measures to diagnose hypogonadism.

Salivary testosterone levels in preadolescent children

BACKGROUND

Saliva reflects the plasma free fraction of testosterone which is biologically active, and available for uptake by tissues. Testosterone concentration in saliva, though differing slightly from the concentration of unbound testosterone in serum, is in good correlation with the latter, indicating that salivary testosterone provides a reliable method for determination of serum free testosterone. The study aimed to investigate salivary testosterone levels and their changes in preadolescent children and to study sexual dimorphism.

METHODS

Testosterone levels were determined in 203 healthy preadolescent children (77 girls and 126 boys) from saliva samples by radioimmunoassay. Sampling was performed once a year with respect to circadian and seasonal fluctuations of testosterone. Data were statistically analyzed by Statgraphic software.

RESULTS

Mean salivary testosterone concentrations (+/- SD) were 0.038 +/- 0.012 nmol/L and 0.046 +/- 0.026 nmol/L for girls and boys, with the medians 0.035 nmol/L and 0.041 nmol/L, respectively. Statistical analysis did not prove changes in salivary testosterone concentrations in the preadolescent period of life, with an exception of the insignificant fall at the age of 7 years, and an insignificant rise at the age of 9 years in girls.

CONCLUSIONS

Generally it can be concluded that salivary testosterone levels in our prepubertal subjects remained stable. There was no significant increase of salivary testosterone levels from the age of 6 until the age of 9 in both sexes. Sexual dimorphism in salivary testosterone levels was proved with significantly higher (p = 0.009) salivary testosterone levels in boys than in girls.

Salivary free testosterone in hirsutism

A sensitive, specific and accurate direct radioimmunoassay of testosterone in human saliva is described. A single salivary testosterone result is shown to be of greater diagnostic use in hirsutism than any of the currently used serum androgen assays. Thus, of 50 hirsute patients, salivary testosterone (Sa-T) was elevated in 34 patients, sex hormone-binding globulin (SHBG) was decreased in 30 women, serum testosterone (S-T) elevated in 13, dehydroepiandrosterone sulphate (DHEA-S) was elevated in 14, and androstenedione in three of the investigated group.

Trace elements in human parotid saliva

Although various proteins and some electrolytes have been measured in human saliva, little systematic data about the major and minor elemental components of this body fluid have been obtained. In order to obtain such data, concentrations of C, Na, P, Cl, K, Ca, Sc, Cr, Fe, Co, Zn, Se, Br, Rb, Sb, I, and Cs in human parotid saliva were measured by instrumental nuclear methods. The data obtained confirmed the relative lack of Zn in saliva of patients with hypogeusia (decreased taste acuity) and suggested that concentrations of Na, Cl, Br, and Ca followed the order: normals greater than hypogeusia greater than hyposmia (decreased smell acuity). To compare concentrations of elements in saliva with those in blood and urine, absolute concentrations were normalized to that of Na through the use of a concept called an enrichment factor. On this basis, parotid saliva is relatively depleted in Se, Zn, and Fe and enriched for most other elements relative to blood plasma indicating that the fluid is not simply a transudate of blood plasma. Using this same technique, saliva composition was found more similar to urine than blood plasma, being relatively depleted in Se, Cs, and Co, being enriched in I, Br, and Cr and having about the same relative concentrations of P, Cl, Zn, Fe, Ca, K, and Rb. As the total body concentrations of many of the enriched elements in saliva are extremely small, their enrichment in saliva suggests special roles for these elements in the oral cavity. Because of its accessibility, ease of collection, and interaction with some body constituents, saliva represents a useful, albeit neglected, tool in the diagnosis of some physiological and pathological changes in body function and in understanding important aspects of trace metal metabolism.

Measurement of testosterone in seminal plasma, saliva and serum by solid-phase enzymeimmunoassay

When testosterone concentrations in serum, saliva and seminal plasma were measured with a solid-phase enzymeimmunoassay in which antitestosterone antibody was bound to CNBr-Sepharose-4B, we found the ratios of testosterone in saliva and seminal plasma to that in serum were 2.5 +/- 0.2% and 5.19 +/- 0.42%. Testosterone level in saliva could be an index of free serum testosterone. In addition, we found a correlation between sperm motility and testosterone level in seminal plasma when sperm motility was measured with a transmembrane migration method. This enzymeimmunoassay could be applied to clinical studies of testosterone.

Low parotid saliva calmodulin in patients with taste and smell dysfunction

Parotid saliva calmodulin was found both in 32 normal volunteers and in 60 patients with taste and smell dysfunction; salivary calmodulin concentration was significantly lower in the patients than in the volunteers. There were no differences in salivary calmodulin concentration with respect to age, sex, or salivary flow rate in either normal volunteers or patients. When patients were categorized by diagnosis, calmodulin concentration was found to be decreased in all patient groups. The concentration of calmodulin in saliva was about 10 times that found in serum, suggesting that the parotid gland is a major source of this protein.

Saliva testosterone time-course response to hCG in adult normal men. Comparison with plasma levels

Testosterone time-course response to 5000 IU hCG was studied simultaneously in the saliva and the plasma of 13 adult normal men. Baseline levels in saliva and plasma were: 93 +/- 9 pg/ml (mean +/- SEM) and 4.9 +/- 0.3 ng/ml respectively. After hCG the same biphasic pattern was observed in both fluids with a similar early response but the delayed peak at 72 h was relatively higher in saliva than in plasma. Thus it was suggested to collect saliva instead of plasma for the evaluation of testicular secretion of testosterone after hCG administration.

Gas chromatography-mass spectrometric analysis of salivary testosterone with reference to diethylstilboestrol-treated prostatic cancer patients

Testosterone has been quantified in saliva by gas chromatography-mass spectrometry with selected ion monitoring of the t-butyldimethylsilyl ether (TBDMS) of the oxime derivative. High specificity of instrumental analysis has been complemented by immunoadsorption for extraction of the analyte. The sensitivity of the detection is approx. 4 pmol/l and the precision of quantification is 3.4% CV for a value of 160 pmol/l and 11% for a value of 25 pmol/l. Female subjects had salivary concentrations of testosterone of 14-52 pmol/l, while testosterone was not detected in the saliva of prostatic cancer patients treated with diethylstilboestrol (DES).

Hormones in saliva

Since the collection of saliva is noninvasive, nonstressful and usually very convenient there have been many recent studies examining the clinical relevance of measuring various hormones in saliva. It now appears that the measurement of most unconjugated steroids in saliva will provide clinically useful data whereas the measurement of conjugated steroids, thyroid hormones, and protein hormones is unlikely to be clinically relevant. The key factors determining whether the salivary concentration of a hormone or drug is likely to be clinically relevant are the mechanisms by which the material enters the saliva; the "free to protein bound" ratio for the material; and the structure of the material, i.e., its molecular weight, polarity and the presence of ionizable groups.

Testosterone concentrations in human seminal plasma and saliva and its correlation with non-protein-bound and total testosterone levels in serum

A sensitive, specific and precise non-chromatographic method for the radioimmunoassay of testosterone in human seminal plasma and saliva from adult and pubertal males is described, and the values compared to total and non-protein-bound testosterone levels in serum. There was a significant correlation between salivary and serum-free levels of testosterone (r = 0.75, P less than 0.001, n = 67) whilst the correlation of serum levels of total testosterone with free as well as with salivary testosterone levels was weaker (r = 0.63 and 0.64, respectively). The salivary and serum levels of free testosterone showed better correlation with the stage of puberty than did the serum levels of total testosterone. Further evidence for a correlation between salivary and serum levels of free testosterone was obtained following oral administration of testosterone undecanoate, as this treatment increased the mean concentration of serum total testosterone after 3 h by 82%, but increased salivary and serum levels of free testosterone by only 30% and 20%, respectively. The coefficient of correlation between serum levels of total testosterone and seminal plasma testosterone was 0.73 (P less than 0.001), whilst the correlation between levels of serum-free testosterone with both salivary and seminal plasma levels of testosterone was statistically non-significant. Our observations on salivary testosterone are in accordance with the diffusion of non-protein-bound steroids into peripheral tissues, and consequently into their secretions. This model, however, does not appear to be applicable to the sex accessory glands.

Estimation of the odorous steroid, 5 alpha-androst-16-en-3-one, in human saliva

The concentration of the urine-smelling steroid, 5 alpha-androst-16-en-3-one, has been measured by radioimmunoassay in the saliva of 9 men and 4 women. The lower limit of detection was estimated to be 0.725 nmoles/l. In six of the men the range of concentrations of the odorous steroid was 0.8-1.8 nmoles/l saliva (3 men had less than the estimated lower limit of detection). In only one of the women studied could the 5 alpha-androst-16-en-3-one be measured (0.83 nmoles/l) in the saliva.

Testosterone and delta 4-androstenedione in the saliva of patients with Klinefelter's syndrome

This study compares salivary and total plasma levels of testosterone and androstenedione in healthy controls and chromatin positive patients with Klinefelter's syndrome. The mean plasma testosterone level in fifteen Klinefelter patients was significantly lower than in ten control subjects, but the mean androstenedione levels were similar. Saliva of the normal men and patients with Klinefelter's syndrome did not differ significantly in binding potency for testosterone or androstenedione. The mean salivary testosterone level in the Klinefelter patients was significantly lower than in the controls but again salivary androstenedione levels were similar. Although testosterone as well as androstenedione showed a fair correlation between the salivary and plasma concentrations, preliminary data suggested that salivary testosterone levels better characterize the clinical state of androgenicity than do plasma levels. When salivary testosterone and androstenedione were expressed as a percentage of total steroid levels in plasma, the ratios for both steroids were similar in Klinefelter patients and healthy controls and closely approximated to the reported percentages of free steroid levels in plasma. The absolute salivary testosterone concentrations also were almost identical to the reported free plasma hormone levels. Together the data provide indirect evidence that in Klinefelter patients testosterone and androstenedione binding in plasma and saliva does not differ from that in normal men, and measurement of salivary steroids, by reflecting their free hormone concentration in plasma, may be useful in evaluating endocrine function in both health and disease.

Oestradiol in saliva during the menstrual cycle

Sixteen women provided saliva samples throughout a menstrual cycle and the concentration of oestradiol was measured. Blood samples were taken around mid-cycle and the luteinizing hormone peak was used to diagnose the timing of ovulation. The levels of oestradiol in saliva followed the same pattern as in blood. The peak of oestradiol in saliva could be used to predict accurately the time of onset of the next menstrual period. The analysis of saliva could be useful in the investigation of women in whom serial venepunctures are not possible.