Bioavailable testosterone in salivary glands (original) (raw)
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A critical evaluation of salivary testosterone as a method for the assessment of serum testosterone
Steroids, 2014
Although salivary testosterone (T) is often used in clinical studies accuracy is mostly questionable. State of the art data for men is sparse and for women absent. Our objective was to perform a critical evaluation of salivary T (Sal-T) as a method for indirect assessment of serum T using state of the art methods. Saliva was collected via 'Salivette' and 'passive drooling' methods. SalT and free T in serum after equilibrium dialysis were measured by LC-MS/MS Results: Evaluation of SalT results versus free T by equilibrium dialysis (ED-T) for men gave: 'Salivette' SalT = 0.05 + 0.88x ED-T, r = 0.43; 'passive drooling' SalT = 0.17 + 0.91x ED-T r = 0.71. In women, correlation was comparable but values are higher than free T: 'passive drooling' SalT = 0.12 + 2.32x ED-T, r = 0.70. The higher than expected T values in saliva, appear to be explained by T binding to salivary proteins. Iso-electric focusing of saliva proteins, followed by fractionation and LC-MS/MS assay of T showed marked testosterone peaks at pH 5.3 and 8.4, providing evidence for T binding in saliva to proteins such as albumin and proline rich protein (PRP). Conclusions: Passive drooling is the collection method of choice for testosterone in saliva. SalT is not directly comparable to serum free T due to T binding to saliva proteins, which substantially affects the low SalT in women but not the higher SalT in healthy adult men.
Clinica Chimica Acta, 1990
We compared unbound (free) testosterone radioimmunoassay concentrations in plasma and saliva from men, using a direct radioimmunoassay kit involving a ligand analog of testosterone as tracer. The assay failed to reveal detectable testosterone concentrations in saliva. In plasma the free testosterone levels were about 4 times lower than those obtained by calculation or ultr~iltration methods. Moreover, unexpected similar free testosterone levels were obtained in samples comparable in their total testosterone content but distinct in their steroid binding protein content (buffered testosterone dilutions). We suspect that free testosterone levels determined with this direct radioimmunoassay probably do not reflect the true free testosterone values and conclude that their significance remains to be established.
Testosterone in human studies: Modest associations between plasma and salivary measurements
Andrologia, 2017
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.
Ratios of plasma and salivary testosterone throughout puberty: Production versus bioavailability
Steroids, 1996
Because diffusion of testosterone (T) into the salivary gland is thought to be largely limited to the free, biologically active fraction, salivary testosterone is expected to provide a better measure of testosterone bioavailability in the body than is plasma testosterone. Matched saliva and blood spot samples were collected from 218 Zimbabwean males (age 11-23) who were at different stages of puberty, as assessed by self-reported Tanner genital stage ratings. Testosterone concentrations in these matched samples were highly correlated (r = 0.83). Both salivary and plasma testosterone (converted from blood spot value) showed expected significant increases across puberty. However, plasma testosterone distinguished among subjects at different stages of genital development more effectively than did salivary testosterone, suggesting the former to be a better marker of testosterone bioavailability. Sex hormone-binding globulin (SHBG) levels were also measured in a subgroup of 93 of these subjects. After controlling for plasma T concentrations, we found a small but significant inverse correlation between blood spot SHBG levels and the proportion of plasma testosterone recovered in saliva, supporting the hypothesis that SHBG-related changes in T bioavailability are detectable in saliva. We conclude that saliva~ testosterone accurately reflects" testicular production of testosterone, but that neither salivary testosterone nor plasma testosterone is clearly superior to the other as a measure of testosterone bioavailability.
The effects of saliva collection, handling and storage on salivary testosterone measurement
Steroids, 2013
Several endocrine parameters commonly measured in plasma, such as steroid hormones, can be measured in the oral fluid. However, there are several technical aspects of saliva sampling and processing that can potentially bias the validity of salivary testosterone measurement. The aim of this study was to evaluate the effects caused by repeated sampling; 5 min centrifugation (at 2000, 6000 or 10,000g); the stimulation of saliva flow by a cotton swab soaked in 2% citric acid touching the tongue; different storage times and conditions as well as the impact of blood contamination on salivary testosterone concentration measured using a commercially available ELISA kit. Fresh, unprocessed, unstimulated saliva samples served as a control. Salivary testosterone concentrations were influenced neither by repeated sampling nor by stimulation of salivary flow. Testosterone levels determined in samples stored in various laboratory conditions for time periods up to 1 month did not differ in comparison with controls. For both genders, salivary testosterone levels were substantially reduced after centrifugation (men F = 29.1; women F = 56.17, p < 0.0001). Blood contamination decreased salivary testosterone levels in a dose-dependent manner (men F = 6.54, p < 0.01, F = 5.01, p < 0.05). Salivary testosterone can be considered A robust and stable marker. However, saliva processing and blood leakage can introduce bias into measurements of salivary testoterone using ELISA. Our observations should be considered in studies focusing on salivary testosterone.
Gender Differences in the Validity of Testosterone Measured in Saliva by Immunoassay
Hormones and Behavior, 2002
We rigorously evaluated gender differences in the measurement validity of salivary testosterone. Matched serum, saliva, and finger stick blood spot specimens were collected from 40 (20 males) young adults (aged 18 -27 years). Saliva was assayed for testosterone by two independent (isotopic and non-isotopic) immunoassay methods. Serum was assayed by commercially available immunoassay kits for free and total testosterone. An immunoassay was developed for the measurement of testosterone in dried blood spots and is presented in detail so as to be reproducible from this report. Regardless of assay method, salivary testosterone levels are modestly correlated with serum levels for males but not necessarily for females. Blood spot assay results were highly correlated with serum total and free testosterone for both males and females. Substitution of saliva assay results for serum values substantially underestimates known testosterone-behavior associations, and this effect is much more pronounced for females than for males. The findings have important implications for the use and potential misuse of noninvasive measures of testosterone, and with respect to statistical power, the probability of observing significant testosterone-behavior relationships. © 2002 Elsevier Science (USA)
Serum Bioavailable Testosterone: Assayed or Calculated?
Clinical Chemistry, 2006
Background: Bioavailable testosterone (BT), circulating testosterone not bound to sex hormone-binding globulin (SHBG), is thought to easily penetrate cells. We compared BT measurements obtained by assays with those obtained by calculation with different testosterone association constants. Methods: We obtained sera from 2 groups of hypogonadal men [group 1 (G1), 1421 samples; group 2 (G2), 170 samples] and a group of healthy men [group 3 (G3), 109 samples]. We added minute doses of [ 3 H]testosterone to the sera, precipitated the SHBG-bound fraction of testosterone with ammonium sulfate (50% saturation), and then assayed serum BT (ABT) as %BT ؋ total. Calculated BT (CBT) was determined with theoretical association constants of testosterone for SHBG (K s ؍ 1 ؋ 10 9 L/mol) and albumin (K a ؍ 3.6 ؋ 10 4 L/mol) and paired optimal K s and K a values obtained by use of Microsoft Excel software. Results: CBT calculated with theoretical constants differed from ABT by >30% in 85.7% (G1), 84.1% (G2), and 77.9% (G3) of samples, and the mean CBT/ABT ratios were 1.57 (G1), 1.85 (G2), and 1.50 (G3) in spite of fairly good correlations. CBT calculated with paired optimal K s and K a differed from ABT by <30% in 87.4% (G1), 87.5% (G2), and 97.5% (G3) of samples, and mean CBT/ABT ratios were 0.95-1.04. Conclusions: To obtain CBT values as close as possible to ABT, optimal paired association constants determined for each studied population must be used instead of the theoretical association constants. Considering the uncertainty of calculating BT, however, use of the ammonium sulfate precipitation method for determining BT is advisable.
Endocrine Abstracts, 2015
Background Recently, measurements of steroids like testosterone, androstenedione, cortisol and cortisone in saliva are more and more applied in diagnostics and scientific studies. This is mainly due to the simple and non-invasive collection of saliva. We aimed to evaluate the optimal way to collect saliva for steroid hormone measurement. Methods We investigated in twenty volunteers whether there is a difference between steroid hormone concentrations in unstimulated and stimulated saliva collected while chewing, using cotton and synthetic Salivettes®, citric acid or chewing gum. Furthermore, total unstimulated saliva was compared to parotid gland saliva. Testosterone, androstenedione, cortisol and cortisone were measured using Liquid-Chromatography Tandem Mass Spectrometry (LC-MS/MS). Results Salivary testosterone, androstenedione and cortisol concentrations were unaffected by stimulation upon mouth and tongue movements, cortisone levels were on average 16% lower. Concentrations of all hormones were lower in parotid gland saliva compared to total unstimulated saliva (on average 51%, 26%, 66% and 49% lower, for testosterone, androstenedione, cortisol and cortisone, respectively). Concentrations of testosterone as well as androstenedione were lower when using synthetic Salivettes® (58% and 41%, respectively) and were higher when using cotton Salivettes® (217% and 46%, respectively). Cortisol levels in saliva were unaffected by using Salivettes®. However, cortisol and testosterone levels were higher in with chewing gum stimulated saliva (16% and 55%, respectively). Cortisone concentrations were lower in all types of stimulations (on average 25%-35%). Conclusion The way saliva is collected should be considered when analysing and interpreting salivary hormone concentrations. We advocate unstimulated saliva collection in simple polypropylene tubes for all steroid measurements.
Salivary testosterone: a reliable approach to the diagnosis of male hypogonadism
Clinical Endocrinology, 2007
Objective This study was to demonstrate that SalT 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 cutoff values were defined. Patients and methods We studied 52 eugonadic (E) and 20 hypogonadic (Hy) men. SalT was assayed using an adapted radioimmunoassay for serum testosterone. SalT 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 SalT did not depend on salivary flow rate and morning samples from 07•00 h to 09•00 h were stable. Agreement between SalT and Free-T measurements was confirmed in all subjects. SalT 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 cutoff value of SalT ≤ 0•195 n m showed 100% sensibility and specificity to rule out hypogonadism. Conclusions Our data showed that SalT 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.