A simple method for estimating equilibrium constants for serum testosterone binding resulting in an optimal free testosterone index for use in elderly men
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H. Alec Ross
Abstract
An algorithm was developed to evaluate equilibrium constants for testosterone (Te) and sex hormone-binding globulin (SHBG) or albumin from serum free testosterone (FTe) measurements performed in a panel of 30 healthy elderly men by means of a near-reference method, i.e., symmetric dialysis (affinity constants: SHBG-Te, 1.13×10 9L/mol; albumin-Te, 4.4×10 4L/mol). Using these estimates, a free testosterone index (FTeI) was calculated from total Te and SHBG concentrations in a further 35 elderly men. This FTeI perfectly matches with actually measured free testosterone concentrations by symmetric dialysis in this second group, with a mean ratio index/measurement of 0.998±0.016 (SEM). The efficacy of the algorithm, which represents a simple alternative to previous cumbersome methods for estimation of equilibrium constants, is thereby demonstrated.
References
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Artikel in diesem Heft
- Spectrophotometric determination of urinary iodine by the Sandell-Kolthoff reaction subsequent to dry alkaline ashing. Results from the Czech Republic in the period 1994–2002
- Comparison of iodine contents in gastric cancer and surrounding normal tissues
- Effects of urine dilution on quantity, size and aggregation of calcium oxalate crystals induced in vitro by an oxalate load
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- Standardized quantification of circulating peripheral tumor cells from lung and breast cancer
- Plasma homocysteine and markers for oxidative stress and inflammation in patients with coronary artery disease – a prospective randomized study of vitamin supplementation
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