Question for the Doctors.

[love_en]

What does having an ACTH stim test done at the same time as a total T blood draw do? Will it elevate or lower T levels. I remember my endo suggesting that my total T levels are actually higher than the 388ng/dl he saw because the increased cortisol would depress T levels. I thought the feedback mechanism took longer than 1 hour to react to the elevated cortisol levels caused by ACTH. I would love to hear HeadDoc's or marianco's thoughts on this one. Swale is also invited.

[marianco]

This is an interesting subject - illustrating the interactions between the hormonal systems.

The brain, in response to stress, directs the pituitary to release Adrenocorticotropic Hormone (ACTH).

ACTH (be it from the pituitary or by injection in the ACTH stimulation test) increases steroid hormone production in the adrenals within minutes if not seconds. Obviously, the body has to be able to respond very quickly to stress. The hormones produced include Cortisol, Progesterone, DHEA, and androsteinedione. A small amount of testosterone is created in the adrenals from androsteinedione. Androsteinedione, which is released, can be converted by the testes to testosterone. Total adrenal production of testosterone is about 5% of total testosterone production.

As far as I know, except in some cases of premature puberty, the mature testes do not increase testosterone production in response to ACTH.

Cortisol, in chronically high concentrations such as in Cushing's disease, can eventually cause reduction in sensitivity to gonadotropin-releasing hormone (GnRH) in the pituitary, thus a reduction in follicle stimulating hormone (FSH) and luteinizing hormone (LH), which in turn will reduce testosterone production. However, as far as I know, the single burst of ACTH during the ACTH stimulation test may not cause such a long enough duration in high cortisol level to cause GnRH resistance.

Thus, I would expect the ACTH Stimulation Test to cause a small increase in testosterone production overall.

Interestingly, testosterone, itself, not only reduces ACTH production in the pituitary, it also directly causes the adrenals to reduce production of Cortisol. Testosterone, thus, serves as a normalizing response to the stress response. Without testosterone, a person has less of an ability to handle stress.

[love_en]

IOW, having an ACTH stim test could cause Total T to be a little higher than it actually is. I now have a reason why my total T was 352ng/dl no ACTH and 388ng/dl after ACTH. My endo obviously cannot be trusted when adrenal or sexual hormones are involved. He does not know what he is talking about.

[Brennon]

My T went into the lower 400s when adminstered the ACTH test. It never broke 200 previously. My endo used it as reason to deny TRT.

[SWALE]

BTW, 352 and 388 are the same thing (within laboratory error).

[love_en]

Thanks. Either of those two are low for a 33 year old.