| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2195963 | Molecular and Cellular Endocrinology | 2015 | 7 Pages |
•We studied the affinity of hSHBG for testosterone by surface plasmon resonance.•The affinity constant decreased significantly when hSHBG concentration increased.•This result may question the validity of methods for calculating free testosterone.
A wide range of human sex hormone-binding globulin (hSHBG) affinity constants for testosterone (KA_hSHBG) has been reported in literature. To bring new insight on the KA_hSHBG value, we implemented a study of the molecular interactions occurring between testosterone and its plasma transport proteins by using surface plasmon resonance.The immobilization on the sensorchip of a testosterone derivative was performed by an oligoethylene glycol linker. For different plasmas with hSHBG concentrations, an assessment of the KA_hSHBG was obtained from a set of sensorgrams and curve-fitting these data. We observed that KA_hSHBG decreased, from at least two decades, when the plasma hSHBG concentration increased from 4.4 to 680 nmol/L. Our study shows a wide biological variability of KA_hSHBG that is related to the hSHBG concentration. These unexpected results may have a physiological significance and question the validity of current methods that are recommended for calculating free testosterone concentrations to evaluate androgen disorders in humans.
