Bigger Guy = More Blood = More Testosterone?

When you have a test for the amount of testosterone in your blood, they show the results usually in nanograms (ng) per deciliter (dl) of blood.
You have two people, each with lab results showing 500ng/dl. Guy number one is a tiny man, 160cm and of narrow proportions, with obviously less blood circulating in his body. Guy number two is a big man, 200cm and broad-shouldered with obviously a lot more blood circulating in his body.
Does guy number two have more testosterone than guy number one?

 

No idea, im 1.90m but im pretty sure that you would also have a bigger body to feed, thereby it evens out in blood:total amount ratio id say? just a thought.

 

Yes, but a smaller guy with the same amount of testosterone / unit of blood will have more effective testosterone levels.

 

exactly.

 

Why is that? Because it's quicker for the T to circulate to receptors?

 

Because you have more testosterone per LBM.

 

It is measured not as total testosterone but per unit volume. The value can be the same in an ant (assuming ants have testosterone) as in an whale. Yes the larger man has more testosterone total but it doesn't matter as he has more tissue the testosterone needs to exert its effects in.

 

What matters is the concentration your tissues are exposed to, which is going to depend on the blood concentration. LBM or height or weight or whatever else shouldn't matter much.

 

That's not entirely true.

The same serum concentration for vastly different body sizes (LBM) is going to be different for tissue exposure.

How different is difficult to quantify, and will need someone to spread some data. For an organ like the brain, it may be the opposite, as in same serum cocnentration for bigger body sizes will increase tissue concentration.

 

Why?

 

Because testosterone/LBM drops as you go bigger, on equal serum concentrations.

 

Why does this matter?

 

More total, but it's the ratio that counts.... Amateur hour

 

It means you have less testosterone per pound of lean body mass, this is going to have more of an effect on bones and muscle, as organs don't grow as much with increasing body size.

For the same serum concentrations, and gonadal hormone ratios, you have less testosterone to androgen receptor density, and effectively, less testosterone.

 

Doesn't matter, testosterone binding to its receptor is a chemical reaction, which will depend only on the concentration of testosterone. A particular testosterone molecule and receptor know nothing about the total number of testosterone molecules in the body or total LBM. The amount of receptor bound depends only on the local testosterone concentration.

 

A bigger man was once small(er), so if he grew to such size, wasn't it due to more androgen receptor density?
Edit: and that the testosterone was more than enough, hence the size.

 

As far as I know, in terms of what's necessary for growth it seems it's igf-1. However there are rare cases of "pseudo acromegaly" where igf-1 and growth hormone levels are normal yet they exhibit signs of acromegaly (enlarged body). There are also very tall people with normal igf-1 and growth hormone, and androgens obviously.

I certainly did not produce a lot of androgens in my youth and I was tall from very early on, long before puberty. I wasn't deficient in androgens either compared to my small counterparts. I did meet a guy who looked extremely masculine, he was a white identical version of Mike Tyson. His voice, his teeth (spaces), his face, matched Mike Tyson to a point where you'd think they were related. Also his body odor, which I could smell from far away, was strong. Everything suggested that if not extremely high testosterone, dht or some other androgen, then his androgen receptors must've been very sensitive unlike my own receptors. Or I suspect it may have been high igf-1. I think he was in the top 0.1% of men when it comes to male characteristics. My point is that he had high androgens and was of normal size, close to 1.8 meters (180cm), but as I said his bones looked like a monster, like Mike Tyson with his short limbs and scary face.

 

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

 

1) There is more to growth than estrogen, except for muscle tissue
2) If we were to assume that density is not constant, then higher density before puberty would lead to more muscle mass on the same AUC (volume) of testosterone, until density normalizes through larger tissue.

I do not know if this what happens in real life, just a thought.

 

Aromatase insufficiency delays long bone growth.