[URL unfurl="true"]https://tru-t.org/[/URL]
The new dynamic model leads to the reconsideration of several dogmas related to testosterone's binding to SHBG and has important physiologic and clinical implications.
*First, the fraction of circulating testosterone that is free is substantially greater (2.9±0.4%) than has been generally assumed (% cFTV 1.5±0.4%).
*Second, percent FT is not significantly related to total testosterone over a wide range of total testosterone concentrations. However, the percent FT declines as SHBG concentrations increase, although it does not decline as precipitously as predicted by Vermeulen's model. Due to the allostery between the two binding sites, SHBG is able to regulate FT levels in a much larger dynamic range.
Key points:
EAM (cFTZ) SHBG: T binding
*Intra-dimer complex allostery suggests that SHBG can regulate FT fraction over a wide range of total testosterone concentrations without getting saturated.
*Indeed, it was found that percent FT calculated using the new model changed very modestly over a wide range of total testosterone concentrations.
*Due to the allostery between the two binding sites, SHBG is able to regulate FT levels in a much larger dynamic range.
