Bigger Guy = More Blood = More Testosterone?

[TheDrumGuy]

That's overly-simplified. Pharmacokinetics takes into account testosterone exposure and receptor density.

Right, it depends on testosterone concentration and receptor concentration.

Bigger tissue should have more absolute receptors, and thus higher relative density compared to slightly more testosterone molecules from a bigger person. Thus, less androgen receptor dimierization/signaling.

Bigger tissue also has more volume. Twice the volume, twice the receptors; density is receptors divided by volume, and the 2's cancel out when you calculate density.

 

[RedStaR]

Bigger tissue also has more volume. Twice the volume, twice the receptors; density is receptors divided by volume, and the 2's cancel out when you calculate density.

Exactly.

 

[DavePalumbo]

Aromatase insufficiency delays long bone growth.

I stopped growing around the age of 13.. and then I was over 2 meters
My arms are short but my legs are as you'd expect for this height, long.

 

[RedStaR]

I stopped growing around the age of 13.. and then I was over 2 meters
My arms are short but my legs are as you'd expect for this height, long.

What's your height and wingspan

 

[DavePalumbo]

What's your height and wingspan

207cm height, 208cm wingspan. It seems my arms are long judging by the wingspan being longer but this is actually short. It's normal to have 5-7cm plus your height in wingspan.

 

[RedStaR]

207cm height, 208cm wingspan. It seems my arms are long judging by the wingspan being longer but this is actually short. It's normal to have 5-7cm plus your height in wingspan.

You might have a long torso and shorter long bones.

Check your ratios and compare to the average.

 

[DavePalumbo]

You might have a long torso and shorter long bones.

Check your ratios and compare to the average.

 

[TheDrumGuy]

Exactly.

So same testosterone concentration, same receptor density...

 

[RedStaR]

So same testosterone concentration, same receptor density...

But less testosterone/receptor.

 

[TheDrumGuy]

But less testosterone/receptor.

Same test concentration / receptor concentration. We're back to square one. The chemical reaction of binding depends only on the substrate concentrations.

 

[RedStaR]

Same test concentration / receptor concentration. We're back to square one. The chemical reaction of binding depends only on the substrate concentrations.

So if I put androgenic tissue in 0.5 and 1L of blood with the same 500ng/dl of testosterone concentration, do I get the same receptor occupancy at the same tmax?

 

[TheDrumGuy]

So if I put androgenic tissue in 0.5 and 1L of blood with the same 500ng/dl of testosterone concentration, do I get the same receptor occupancy at the same tmax?

Immersing a lump of tissue in blood, the total volume of blood makes no difference for short periods of time. Are you saying that the testosterone concentration in the blood will drop with time as testosterone enters the cells? In vivo your testes are producing testosterone to keep serum levels constant. The larger guy's testes are producing more testosterone to maintain 500ng/dL

 

[RedStaR]

Immersing a lump of tissue in blood, the total volume of blood makes no difference for short periods of time. Are you saying that the testosterone concentration in the blood will drop with time as testosterone enters the cells? In vivo your testes are producing testosterone to keep serum levels constant. The larger guy's testes are producing more testosterone to maintain 500ng/dL

I see where we differ. My main point of argument is that testosterone has a very short-half life in blood, so once it dissociates, it's gone. Testes produces testosterone in pulses, and occupying a larger number of receptors will deplete serum concentrations more quickly for a larger guy. It was a simple Vd*C0<TR process.

Ligand-receptor kinetics are more complicated than this, not to mention androgen receptor pharmacodynamics. I don't know the real answer. Maybe 50% occupancy will achieve maximum response, or dimierization lasts a whole day. Someone need to dig up a study looking at this issue in particular, I assume the differences will be small since we haven't heard about size (NOT fat) being a problem for testosterone concentrations.

 

[fradon]

bigger man more growth hormone more estrogen...some of the biggest T guys are skinny with deep voices and huge adams apples.

 

[Ron J]

bigger man more growth hormone more estrogen...some of the biggest T guys are skinny with deep voices and huge adams apples.

I find a deep voice and masculine face more impressive when a large male has it because I assume that it required way more testosterone/DHT/growth hormone to achieve that, compared to smaller men. I think it's the lower likelihood of being very high testosterone and large.