Age and Abdominal Visceral Fat in Reducing AR-Dependent Negative Feedback

[Michael Scally MD]

Takahashi PY, Liu PY, Veldhuis JD. Distinct roles of age and abdominal visceral fat in reducing androgen receptor-dependent negative feedback on LH secretion in healthy men. Andrology. Distinct roles of age and abdominal visceral fat in reducing androgen receptor-dependent negative feedback on LH secretion in healthy men - Takahashi - 2014 - Andrology - Wiley Online Library

Testosterone (T) impacts luteinizing hormone (LH) secretion through negative feedback via the androgen receptor (AR) in the hypothalamo-pituitary system.

An untested postulate is that increasing body mass index (BMI), abdominal visceral fat (AVF) or total abdominal fat (TAF) with ageing decreases LH secretion by heightening T negative feedback via AR.

This hypothesis was tested in a prospective, randomized double-blind cross-over study of 19 healthy men comparing the effects of flutamide, a selective non-steroidal AR antagonist and placebo administration on basal and pulsatile LH secretion as a function of age and obesity measures.

To this end, serum levels of 2-hydroxyflutamide (2-OHF), a major active flutamide metabolite, were measured by mass spectrometry, and AVF/TAF quantified by abdominal computerized tomography.

Statistical analysis showed that antiandrogen administration elevated 6-h mean LH concentrations to 5.4 ± 1.3 IU/L compared with 3.3 ± 1.2 IU/L for placebo (p < 10?3), and total T by 35% (p < 10?4). The LH-T concentration product doubled (p < 10?8). According to deconvolution analysis, flutamide exposure increased total LH secretion (p < 10?3) and pulsatile LH secretion (p = 0.0077), along with LH pulse frequency (p = 0.019).

Despite feedback inhibition, the LH-T product declined as a linear function of AVF (p = 0.021) and TAF (p = 0.017). This was explained by the fact that higher BMI was associated with lower 2-OHF concentrations (R = ?0.562, p = 0.012).

In contrast, age was associated with less pulsatile LH secretion (R = ?0.567, p = 0.011) even when LH responses were normalized to antiantrogen levels.

In conclusion, increased AVF, TAF and BMI predict decreased LH and flutamide blood levels, whereas older age is marked by impaired stimulation of pulsatile LH secretion even when normalized for antiandrogen levels, suggesting different mechanisms of regulation by adiposity and age.

 

[blazinshotguns]

My bmi is 35 that's bad right ?

 

[TheGuy85]

I don't think bmi table is accurate for people with a lot of muscle mass. You could have a bmi level that indicates you are overweight but you could be shredded and in great shape.

 

[blazinshotguns]

^ no I'm not shredded . I'm quite the opposite

 

[TheGuy85]

Best way to determine if you are "fat" or obese is to measure body fat % and look at a table of percentages that reflects what %s your considered overweight or obese.

I thought u were joking about being 35 BMI but if it's true you are considered obese by BMI chart standards. I'm considered overweight (though barely) by the reference ranges I have found and I am by no means fat. I am 173 today but I will have to drop down to 170 and I would probably be at "normal" them. But if I bump up a weight class and go to 185 I am heavier but definitely not fat. I frequently go up into the 180s and then have to drop back down to 170.

But if your BMI is honestly 35 and your not diesel (big and muscular) you are probably fat. I would have to be like 210 lbs at 5'10" to reach 30 BMI. I have ventures as high as mid-upper 190s but I had a gut with that weight, though I wasn't terribly fat and was still active.

There are plenty of bodybuilders, in particular, that are considered obese by BMI ranges and they are definitely not fat. Some power lifters too, but serious power lifters will put on weight however they can get it fat or muscle or water. Some power lifters I know are bigger than bodybuilders I know and have a way better physique. I know a couple natty power lifters that have body builder-like physique, I also know a few that are big and muscular but carrying a little fat. And I know a couple that are damned fat.

 

[TheGuy85]

To think about it I have a buddy that lifted natty and he was fucking ripped at 205-215 and he was about 2 inches shorter than me. At one time he has a little bit of a gut going on but he eventually had a flat hard stomach in the 200s. Last time I seen him I dunno how heavy he was but it was at least 205 and he told me to "get my weight up". He may have been 215 with a little stomach fat and dropped to 205, slowly, and kept lifting and the fat was gone.

 

[Michael Scally MD]

I don't think bmi table is accurate for people with a lot of muscle mass. You could have a bmi level that indicates you are overweight but you could be shredded and in great shape.

I am sure that none of the subjects was a BB. Veldhuis is the best when it comes to the HPTA. But, your point is well taken.