Calculation of free and bound fractions of testosterone and estradiol-17β to human plasma proteins at body temperature

Södergård, R.; Bäckström, Torbjörn; Shanbhag, Vithaldas P.; Carstensen, Helena

doi:10.1016/0022-4731(82)90038-3

Cited by 996 publications

(698 citation statements)

References 38 publications

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“…Additionally, small volume of serum (approximately 0.5 ml) available for this study precluded the direct measurement of bioavailable testosterone. Therefore, we used the methods of Söderberg et al 19 to compute bioavailable testosterone concentrations, a method that has been shown to be highly sensitive and specific. 20 In summary, the results of this longitudinal study of young to middle-aged men indicate that SHBG increases with age for those whose BMI remains stable, but this increase is attenuated with increasing BMI.…”

Section: Discussionmentioning

confidence: 99%

“…The intra-and inter-batch technical errors were 12.3 and 11.2%, respectively, for total testosterone and 7.9 and 11.2%, respectively, for SHBG. The concentrations of bioavailable testosterone were calculated according to the method of Södergard et al 19,20 The age-and BMI-adjusted partial correlations between time of blood draw and all hormone levels were p0.09. Thus, the relationships between time of blood draw and hormone levels were not considered further.…”

Section: Hormone Measurementsmentioning

confidence: 99%

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Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study

et al. 2006

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Objectives: To compare age-associated 8-year changes in total testosterone, calculated bioavailable testosterone and sex hormone binding globulin (SHBG) across five groups of men stratified according to change in body mass index (BMI) (i.e., BMI stable (70.69 kg/m 2 ), decreased (À0.7 kg/m 2 ), increased minimally (0.7-1.74 kg/m 2 ), increased moderately (1.75-3.19 kg/m 2 ) and increased most (X3.20 kg/m 2 )). Design: Eight-year longitudinal cohort study. Subjects: Four hundred and seventy-four black and 695 white men, aged 24-31 years at the time of the first hormone measurement. Measurements: Aging-related changes in serum SHBG, total testosterone and bioavailable testosterone. Results: SHBG significantly increased with age for men whose BMI decreased, and there were progressively smaller increases for men whose BMI was stable, or whose BMI increased minimally or moderately (range 1.1-0.3 nM per year, Pp0.03, respectively). There was no age relationship with SHBG among men whose BMI increased most. Total testosterone did not change with age for men whose BMI decreased, was stable or increased minimally, but for men whose BMI increased moderately and most there was a graded decrease in total testosterone with age (b ¼ À0.2 and À0.4 nM per year, respectively, Pp0.005). However, bioavailable testosterone decreased with age to a similar extent across all groups. Conclusions: These results suggest that changes in BMI during young adulthood modulate age-related changes in SHBG and total testosterone, but not bioavailable testosterone.

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Section: Discussionmentioning

confidence: 99%

Section: Hormone Measurementsmentioning

confidence: 99%

Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study

et al. 2006

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“…There was no association between time of blood draw and hormone levels (Gapstur et al., 2002). Bio‐T levels were calculated based on the Sodergard et al., method (Södergard, Bäckström, Shanbhag, & Carstensen, 1982; Vermeulen, Verdonck, & Kaufman, 1999). …”

Section: Methodsmentioning

confidence: 99%

Sex hormones and brain volumes in a longitudinal study of middle‐aged men in the CARDIA study

et al. 2017

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IntroductionSeveral findings suggest that testosterone (T) is neuroprotective and that declining T levels during aging are associated with cognitive and brain pathologies; however, little is known on T and brain health in middle‐age. We examined the relationships of total T, bioavailable T, and sex hormone binding globulin (SHBG) levels with total and regional gray matter (GM) and white matter (WM) volumes in middle‐aged men. We also evaluated the association of sex hormone levels with cognitive function.MethodsAnalysis included 267 community‐dwelling men participating in the Coronary Artery Risk Development in Young Adults (CARDIA) brain magnetic resonance imaging (MRI) substudy. Total T, bioavailable T, and SHBG levels were measured at three times from the 2nd to 4th decade of life; brain volumes were measured at the ages of 42–56. Associations were estimated using linear regression models, adjusted for several potential confounders.ResultsHigher SHBG levels were associated with greater total WM volume (+3.15 cm3 [95% confidence interval [CI] = 0.01, 6.28] per one standard deviation higher SHBG). Higher SHBG levels were associated with lower total and regional GM volumes overall and significantly with smaller parietal GM volume (−0.96 cm3 [95%CI = −1.71, −0.21]). T levels were not related to brain volumes. Neither T nor SHBG levels were associated with cognitive function.ConclusionResults suggest a role for SHBG in structural brain outcomes in men and emphasize the value of investigating SHBG levels as modulators of sex hormone and metabolic pathways regulating brain and behavioral characteristics in men.

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“…Assay sensitivities and interassay precision are less than 10 pg/mL and 10%, respectively for E 1 and less than 2 pg/ml and 8% for E 2 . Free (non-SHBG bound) E 2 was estimated based on serum SHBG and total E 2 levels [35]. A Total Testosterone 125 I RIA Kit, supplied from Diagnostic Products Corporation (DPC) was utilized with sensitivity as 4 ng/dL and an inter-assay precision of 5.9-11%.…”

Section: Blood Collection and Hormone Measurementsmentioning

confidence: 99%

An association between a common variant (G972R) in the IRS-1 gene and sex hormone levels in post-menopausal breast cancer survivors

Fan

McKean‐Cowdin

Bernstein

et al. 2006

Breast Cancer Res Treat

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Insulin receptor substrate-1 (IRS-1) is a key downstream signaling molecule common to both the insulin and IGF signaling pathways that can interact with the estrogen pathway to regulate breast cell growth. We investigated whether a putative functional variant for IRS-1 (G972R) influences circulating levels of sex hormones, sex hormone binding globulin (SHBG), C-peptide, and insulinlike growth factor 1 (IGF-1) levels among postmenopausal African-American and non-Hispanic white breast cancer patients enrolled in the Health, Eating, Activity, and Lifestyle (HEAL) Study. Circulating levels of sex hormones and growth factors can influence breast cancer recurrence and survival. Serum estrone, estradiol, testosterone, SHBG, IGF-1 and C-peptide were measured in 468 patients at 30+ months post diagnosis. Non-protein bound hormone levels (free estradiol, free testosterone) were calculated. In African-American patients, the IRS-1 variant was associated with increased serum levels of estrone (p=0.02), free estradiol (p=0.04), total testosterone (p=0.04), free testosterone (p=0.006) and decreased levels of sex hormone-binding globulin (p=0.02). No association was present for white patients. Our findings provide suggestive evidence that IRS-1 G972R variant may be associated with circulating levels of sex hormones and SHBG in African American breast cancer survivors.

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Calculation of free and bound fractions of testosterone and estradiol-17β to human plasma proteins at body temperature

Cited by 996 publications

References 38 publications

Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study

Changes in BMI modulate age-associated changes in sex hormone binding globulin and total testosterone, but not bioavailable testosterone in young adult men: the CARDIA Male Hormone Study

Sex hormones and brain volumes in a longitudinal study of middle‐aged men in the CARDIA study

An association between a common variant (G972R) in the IRS-1 gene and sex hormone levels in post-menopausal breast cancer survivors

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