scholarly journals Age-Associated Discrepancy between Measured and Calculated Bioavailable Testosterone in Men

2007 ◽  
Vol 53 (4) ◽  
pp. 723-728 ◽  
Author(s):  
Henri Déchaud ◽  
Anne Denuzière ◽  
Sabina Rinaldi ◽  
Julien Bocquet ◽  
Hervé Lejeune ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Older Men ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Plasma Samples ◽  
Aging Male ◽  
Ammonium Sulfate Precipitation ◽  
Male Population ◽  
Bioavailable Testosterone ◽  
Parallel Increase

Abstract Background: Bioavailable testosterone (BT) concentration is considered the best marker for evaluating testicular function in men. The decrease of BT in older men is more pronounced than the decrease in total testosterone because of the parallel increase in sex hormone–binding globulin (SHBG) concentrations. Measurement of BT is therefore crucial for the diagnosis of hypoandrogenism in the aging male population. Methods: We compared BT concentrations measured by a specific RIA after ammonium sulfate precipitation (BTmeas) with those obtained by theoretical calculations (BTcal) in plasma samples from 694 young men (14 to 49 years old) and 51 older men (50 to 81 years old). We based theoretical calculations on Vermeulen’s simplified mass equation using total testosterone and SHBG concentrations. Results: BTcal and BTmeas correlated significantly in young (Pearson r = 0.87) and aging (r = 0.89) men, but the BTcal:BTmeas ratio differed markedly between the 2 groups (2.28 vs 3.48; P <0.001). Conclusions: In men, there is an age-associated discrepancy between calculated and measured BT concentrations. We suggest some hypotheses for the discrepancy, but additional studies will be performed to finally elucidate this difference in results and to determine the most appropriate method for BT measurements in older men.

scholarly journals In men older than 70 years, total testosterone remains stable while free testosterone declines with age. The Health in Men Study

2007 ◽  
Vol 156 (5) ◽  
pp. 585-594 ◽  
Author(s):  
Bu B Yeap ◽  
Osvaldo P Almeida ◽  
Zoë Hyde ◽  
Paul E Norman ◽  
S A Paul Chubb ◽  
...  
Keyword(s):  
Free Testosterone ◽  
Older Men ◽  
Early Morning ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Limited Data ◽  
Cross Sectional ◽  
Testosterone Concentration ◽  
Age Related ◽  
Clinical Consequences

Objective: An age-related decline in serum total and free testosterone concentration may contribute to ill health in men, but limited data are available for men > 70 years of age. We sought to determine the distribution and associations of reduced testosterone concentrations in older men. Design: The Health in Men Study is a community-representative prospective cohort investigation of 4263 men aged ≥ 70 years. Cross-sectional hormone data from 3645 men were analysed. Methods: Early morning sera were assayed for total testosterone, sex hormone binding globulin (SHBG) and LH. Free testosterone was calculated using the Vermeulen method. Results: Mean (± s.d.) serum total testosterone was 15.4 ± 5.6 nmol/l (444 ± 162 ng/dl), SHBG 42.4 ± 16.7 nmol/l and free testosterone 278 ± 96 pmol/l (8.01 ± 2.78 ng/dl). Total testosterone correlated with SHBG (Spearman’s r = 0.6, P < 0.0001). LH and SHBG increased with age (r = 0.2, P < 0.0001 for both). Instead of declining, total testosterone increased marginally (r = 0.04, P = 0.007) whilst free testosterone declined with age (r = −0.1, P < 0.0001). Free testosterone was inversely correlated with LH (r = −0.1, P < 0.0001). In multivariate analyses, increasing age, body mass index (BMI) and LH were associated with lower free testosterone. Conclusions: In men aged 70–89 years, modulation of androgen action may occur via an age-related increase in SHBG and reduction in free testosterone without a decline in total testosterone concentration. Increasing age, BMI and LH are independently associated with lower free testosterone. Further investigation would be required to assess the clinical consequences of low serum free testosterone, particularly in older men in whom total testosterone may be preserved.

Urinary Equol is Associated with Bioavailable Testosterone but not Total Testosterone in Women

2019 ◽  
Author(s):  
Hong-li Dong ◽  
Feng Xiong ◽  
Qing-wei Zhong ◽  
Yi-hong Li ◽  
Meng Liu ◽  
...  
Keyword(s):  
Postmenopausal Women ◽  
Menopausal Status ◽  
Premenopausal Women ◽  
Positive Association ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Significant Positive Association ◽  
Cross Sectional ◽  
Bioavailable Testosterone

Little is known about the association between equol and bioavailable testosterone (BT) in adults. We examined the associations of urinary equol concentrations with serum total, bioavailable and free testosterone (FT), dehydroepiandrosterone sulfide (DHEAS), free androgen index (FAI) and sex hormone-binding globulin (SHBG) concentrations. This cross-sectional study included 1904 women aged 59.7 years. Urinary equol and serum sex hormone concentrations were measured. Overall, urinary equol tended to be inversely associated with bioactive forms of androgenic indices (BT, FT or FAI) but not with total testosterone (TT) or DHEAS. Urinary equol was also positively associated with SHBG. In multi-covariate-adjusted analyses stratified by menopausal status, graded and inverse associations between urinary equol and bioactive forms of androgenic indices (BT, FT and FAI) were observed in postmenopausal women (all p-trends &lt;0.05), but not in premenopausal women. A significant positive association between urinary equol and SHBG was observed only in postmenopausal women. No significant associations were observed between urinary equol and TT or DHEAS in either group. A path analysis indicated that these associations of equol with androgens in postmenopausal women might be mediated by SHBG. Our findings indicated urinary equol exhibited graded and inverse associations with BT or FT but not TT in women.

scholarly journals Testosterone profile in older men with Alzheimer's disease

2008 ◽  
Vol 2 (4) ◽  
pp. 289-293
Author(s):  
Cristiana Roscito Arenella Dusi ◽  
Lílian Schafirovits Morillo ◽  
Regina Miksian Magaldi ◽  
Adriana Nunes Machado ◽  
Sami Liberman ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Free Testosterone ◽  
Older Men ◽  
Sex Hormone Binding Globulin ◽  
Control Group ◽  
Total Testosterone ◽  
Chi Square ◽  
Testosterone Levels ◽  
Significant Difference

Abstract Evidence suggests low testosterone levels in Alzheimer's disease. Objectives: To compare testosterone levels between older men with and without Alzheimer's disease. Methods: Fourteen men with Alzheimer's disease were compared with twenty eight men without dementia. Demographic variables and clinical profiles were analyzed. Within fifteen days before or after the described evaluation, measures of total testosterone and Sex Hormone Binding Globulin (SHBG) were performed. Free testosterone level was calculated based on total testosterone and SHBG. Quantitative variables were analyzed using Student's t test or Kruskal-Wallis test, while qualitative variables were analyzed using chi-square or Fisher test. Results: Mean age in the Control and Alzheimer's disease groups were 72.0 (SD±4.8) years and 79.3(SD±5.9) years, respectively (p=0.001). Mean schooling between these two groups were 8.78 and (±5.86) years, respectively (p=0.022). There were no statistically significant differences between the two groups for testosterone levels, although a trend was observed for the Alzheimer's disease group to present lower levels than the control group (p=0.066). There was no direct correlation between free testosterone and age, although a trend was evident (p=0.068). Conclusions: There was no significant difference in testosterone between men with AD and those without dementia.

scholarly journals Measures of bioavailable serum testosterone and estradiol and their relationships with muscle mass, muscle strength and bone mineral density in postmenopausal women: a cross-sectional study

2009 ◽  
Vol 160 (4) ◽  
pp. 681-687 ◽  
Author(s):  
Tineke A C M van Geel ◽  
Piet P Geusens ◽  
Bjorn Winkens ◽  
Jean-Pierre J E Sels ◽  
Geert-Jan Dinant
Keyword(s):  
Bone Mineral Density ◽  
Muscle Strength ◽  
Postmenopausal Women ◽  
Bone Mineral ◽  
Handgrip Strength ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Mineral Density ◽  
Bioavailable Testosterone ◽  
Age Related

ObjectiveThe physiologic role of circulating endogenous testosterone and estrogen concentrations in relation to lean body mass (LBM) and muscle strength is not as well documented in postmenopausal women as in elderly men.DesignThree hundred and twenty-nine healthy postmenopausal women were randomly selected from a general practice population-based sample aged between 55 and 85 years.MethodsTotal testosterone and estrogen (TT and TE) and sex hormone-binding globulin (SHBG) were determined and estimates of bioavailable testosterone (free androgen index (TT/SHBG, FAI), calculated free testosterone (cFT), and estrogen (TE/SHBG, ESR) were calculated. Examinations included bone mineral density (BMD) of the spine and femoral neck (FN), LBM, maximum quadriceps extension strength (MES) and maximum handgrip strength (MGS), timed up-and-go test (TUGT), osteocalcin (OC), and urinary deoxy-pyridinoline/creatinine (DPyr). Correlations were assessed using Pearson's correlation coefficient (r).ResultsWith advancing age, LBM, MES, MGS, BMD, and ESR significantly declined (ranger: −0.356 to −0.141) and TUGT, and DPyr significantly increased (ranger: 0.135 to 0.282 (P<0.05)). After age-adjustment, LBM, MES, and BMD in spine and FN were significantly related to bioavailable testosterone (ranger: 0.146 to 0.193, for cFT, and 0.157 to 0.224, for FAI) and to ESR (ranger: 0.162 to 0.273). OC and DPyr were significantly inversely related to ESR (r: −0.154 and −0.144 respectively).ConclusionsAge-related loss of LBM, MES and BMD in postmenopausal women is partly dependent on the presence of endogenous bioavailable testosterone and estrogen.

The Effect of Aromatase Inhibition on Sex Steroids, Gonadotropins, and Markers of Bone Turnover in Older Men1

2001 ◽  
Vol 86 (6) ◽  
pp. 2869-2874
Author(s):  
Pamela Taxel ◽  
Dayna G. Kennedy ◽  
Pamela M. Fall ◽  
Alice K. Willard ◽  
Jonathan M. Clive ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Turnover ◽  
Older Men ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Type I ◽  
Aromatase Inhibition ◽  
Bone Specific Alkaline Phosphatase ◽  
Type I Procollagen

There is evidence that estrogen decreases bone turnover in men as well as women. We therefore hypothesized that older men would show increased bone resorption in response to inhibition of the aromatase enzyme, which converts androgens to estrogen. Fifteen eugonadal men over 65 yr were treated for 9 weeks with 2.0 mg/day of anastrozole, an aromatase inhibitor. After 9 weeks of treatment, there were significant decreases in estradiol, estrone, and sex hormone-binding globulin levels by 29%, 73%, and 16%, respectively, and total testosterone increased significantly by 56%. Despite the limited decrease of estrogen and the increase in testosterone, C-telopeptide of type 1 collagen showed a progressive significant increase of 11%, 24%, and 33% (P for trend = 0.033) above baseline at 3, 6, and 9 weeks, respectively. N-telopeptide of type 1 collagen values were highly correlated with C-telopeptide of type 1 collagen, but the change in N-telopeptide of type 1 collagen was not statistically significant. Bone-specific alkaline phosphatase and N-terminal type I procollagen peptides showed significant decreases of 8% and 11% of baseline at 9 weeks. Osteocalcin decreased significantly by 30% at 18 weeks. We conclude that aromatase inhibition can reduce estrogen levels in older men, but this effect is limited, perhaps because of feedback stimulation of testosterone production, and that endogenous estrogen derived from aromatization of testosterone plays a role in bone metabolism of older men by limiting the rate of bone resorption.

scholarly journals Determination of Bioavailable Testosterone [Non–Sex Hormone–Binding Globulin (SHBG)-Bound Testosterone] in a Population of Healthy French Men: Influence of Androstenediol on Testosterone Binding to SHBG

2007 ◽  
Vol 53 (12) ◽  
pp. 2160-2168 ◽  
Author(s):  
Frank Giton ◽  
Saïk Urien ◽  
Catherine Born ◽  
Jean Tichet ◽  
Jérôme Guéchot ◽  
...  
Keyword(s):  
Binding Constants ◽  
Normal Serum ◽  
Association Constants ◽  
Sex Hormone ◽  
Mass Action ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Hormone Binding ◽  
Bioavailable Testosterone ◽  
Age Related

Abstract Background: Bioavailable testosterone (BT) is measured [assayed BT (aBT)] or calculated (cBT) in the diagnosis of hypogonadism in men. The cBT depends, however, on the values of the association constants of total testosterone (TT) for sex hormone–binding globulin (SHBG; Ks) and albumin (Ka), and its use therefore remains controversial. Methods: In 503 selected, untreated healthy men, 20–74 years old, we measured TT, dihydrotestosterone (DHT), and androstenediol (5-diol) by GC-MS, SHBG by RIA, and BT after ammonium sulfate precipitation or by calculation according to the law of mass action. Results: A slight decrease in TT, significant decreases in BT and 5-diol, no variation in DHT, and an increase in SHBG were observed with age. In young males (≤39 years), the lower normal limits were between 2.30 and 2.72 nmol/L for aBT and 8.50 nmol/L for TT. For Ks = 1 × 109 L/mol and Ka = 3.6 × 104 L/mol, the lower cBT limit was found to be 2-fold higher than for aBT. With optimized Ks = 1.9 × 109 L/mol and Ka = 2.45 × 104 L/mol, cBT values close to aBT were obtained. When 5-diol was included in the model as a competitive SHBG inhibitor, the correlation between cBT and aBT was better and the cBT:aBT ratios vs 5-diol were less biased. Conclusion: Lower normal serum aBT concentration in normal men appears to be between 2.30 and 2.72 nmol/L. Much higher serum cBT concentrations are associated with use of different association constants that may be inappropriate. When using the optimized binding constants, taking age-related 5-diol values into consideration slightly improves prediction of cBT.

scholarly journals A mathematical comparison of techniques to predict biologically available testosterone in a cohort of 1072 men

2004 ◽  
pp. 241-249 ◽  
Author(s):  
PD Morris ◽  
CJ Malkin ◽  
KS Channer ◽  
TH Jones
Keyword(s):  
Free Testosterone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Free Androgen Index ◽  
Good Marker ◽  
Bioavailable Testosterone ◽  
Ammonium Sulphate Precipitation ◽  
Comparison Of Techniques ◽  
Operator Curve

OBJECTIVE: In the absence of widely available measures of determining free and/or bioavailable testosterone (BioT) physicians may use formulae such as the free androgen index (FAI) to estimate free testosterone. We compared the efficacy of calculated markers of androgen status in predicting serum BioT and hypogonadism. DESIGN: Total testosterone (TT), sex hormone binding globulin (SHBG) and BioT were determined in a large cohort of men. Comparison of calculated androgen levels was performed following endocrine assessment. METHODS: TT and SHBG were determined by ELISA, and BioT was determined by ammonium sulphate precipitation. From these data we calculated FAI and free testosterone using two other published formulae - FTnw (free testosterone as calculated by the method of Nanjeee and Wheeler) and FTv (free testosterone as calculated by the method of Vermeulen). A novel formula was derived to calculate BioT from given levels of TT and SHBG (BTcalculated). The ability of the methods (FAI, FTnw, FTv, BTcalc) to predict BioT were compared using regression analysis. The ability of these markers of androgen status to predict biochemical hypogonadism was compared using area under receiver operator curve (auROC). RESULTS: The equation derived from our data was the best predictor of BioT (R(2)=0.73, P<0.0001) although TT was also a good marker (R(2)=0.68, P=0.0001). In the determination of hypogonadism, of all currently available formulae none were better that the TT (auROC: TT=0.93, FAI=0.72, FTnw=0.91, FTv=0.88) although when TT is borderline (7.5<TT<12 nmol/l) estimates of free testosterone are superior to TT alone (auROC: TT=0.63, FAI=0.74, FTnw=0.75 and FTv=0.75). CONCLUSIONS: TT is the best marker of hypogonadism and BioT, when TT is borderline calculated indices of free testosterone or BioT are useful and may help confirm hypogonadism.

Determination of testosterone in serum not bound by sex-hormone-binding globulin: diagnostic value in hirsute women.

1988 ◽  
Vol 34 (9) ◽  
pp. 1826-1829 ◽  
Author(s):  
S Loric ◽  
J Guéchot ◽  
F Duron ◽  
P Aubert ◽  
J Giboudeau
Keyword(s):  
Ammonium Sulfate ◽  
Free Testosterone ◽  
Diagnostic Value ◽  
Sex Hormone ◽  
Sex Hormone Binding Globulin ◽  
Total Testosterone ◽  
Hormone Binding ◽  
Ammonium Sulfate Precipitation ◽  
Clinical Value ◽  
Free Androgen Index

Abstract We compared the diagnostic value of information given by total testosterone (I), free testosterone (II), the free androgen index (III), and testosterone not bound by sex-hormone-binding globulin (SHBG) (IV) as measured by a new differential ammonium sulfate precipitation technique, each step of which is conducted at 37 degrees C. SHBG and albuminemia were also measured. To examine the clinical value of IV, we analyzed single blood samples from 15 hirsute women and 15 age-matched healthy control volunteers. Values for I, II, III, and IV testosterone were all significantly higher in the hirsute group (P less than 0.01), whereas SHBG was decreased (P less than 0.01) and albumin concentrations were similar for the two groups. Overlap between values for normal and for hirsute women was 33.3% for I, 13.3% for II, and 0% for III and IV. The presented data suggest that IV measured by ammonium sulfate precipitation is the preferred discriminator for detecting hyperandrogenism, because this assay is technically simpler and less expensive than the II assay for routine investigation. It closely reflects the pool of bioavailable testosterone; thus, its main use might be as a screening test for androgen excess in women.

Sign in / Sign up

Export Citation Format

Share Document