Authoritative evidence that AAS with saturated A-ring structures (e.g., Masteron, Primo, Anavar, Superdrol, Proviron) all inhibit aromatase

[Type-IIx]

Authoritative evidence that AAS with saturated A-ring structures (e.g., Masteron, Primo, Anavar, Superdrol, Proviron) all competitively inhibit aromatase [Author: Type-IIx]



Author: Type-IIx



Aromatase Inhibition by 5α-Reduced C19 Androgens
From [1]:

The 5α-reduced metabolites of testosterone, DHT; 5α-dihydrotestosterone & 5α-androstanedione proved to be competitive inhibitors of the granulosa cell aromatase reaction in vitro.


DHT & 5α-androstanedione Inhibit Aromatase More Potently than a Known AI (Δ¹T; 1-ene-testololactone)

• AIs:
  • ATD: androst-1,4,6-triene-3,17-dione, &
  • Δ¹T: 1-ene-testololactone

Relative potencies (at 10⁻⁶ mol/L vs. testosterone at 10⁻⁷) were: ATD > 5α-androstanedione > DHT > Δ¹T.

In order to test the steroidal specificity of the inhibition of aromatase by (1) DHT & (2) 5α-androstanedione, the effects of these two compounds on the aromatization of testosterone were also compared with those of three other androgen metabolites:

• (3) 5α-androstane-3α,17β-diol (3α-diol)
• (4) 5α-androstane-3β,17β-diol (3β-diol)
• (5) 5β-androstane-3,17-dione, and that of a C-21 steroid, (6) progesterone, that had no effect on aromatization of T

All five C19 steroids – DHT, 5α-androstanedione, 3α-diol, 3β-diol, & 5β-androstane-3,17-dione competitively inhibited aromatase (i.e., reduced T ⇒ E₂) at 10-fold higher concentrations than T. The percentage reductions (-%Δ) in estradiol accumulation were:

73.3% (5α-androstanedione) > 60.4% (DHT) > 49.1% (3β-diol) > 35.0% (5β-androstane-3,17-dione) > 24.3% (3α-diol).

So, in addition to the class antiestrogenic effects of nonaromatizable AAS discussed in [2] – suppression of gonadotropin (LH, FSH) secretion at the pituitary & T in the testis (Leydig cell) thereby reducing aromatase substrates (reducing aromatization to estradiol), and blockade of estrogen uptake at the tissue-cellular level – inhibition of aromatase indeed is evidenced to occur, albeit in rat ovarian granulosa cells. Hey, it’s something.

---

References:

[1] Hillier SG, van den Boogaard AM, Reichert LE Jr, van Hall EV. Alterations in granulosa cell aromatase activity accompanying preovulatory follicular development in the rat ovary with evidence that 5alpha-reduced C19 steroids inhibit the aromatase reaction in vitro. J Endocrinol. 1980 Mar;84(3):409-19. doi: 10.1677/joe.0.0840409

[2] Type-IIx. “Primobolan / Equipoise Crashed my E2 – Help!” MesoRx, 26 Jul. 2023, thinksteroids.com/articles/primobolan-equipoise-crashed-my-e2-help/

 

[I6JQdr06]

I haven’t read the article yet, I’m about to delve in. But just a note that primo doesn’t possess a saturated A ring.

 

[Type-IIx]

I haven’t read the article yet, I’m about to delve in. But just a note that primo doesn’t possess a saturated A ring.

True I did forget it was a Δ¹, however I expect that the trans junction between rings A & B of C-19 steroids is what controls behavior here, expanding this behavior to at least the androst-1-ene-3-ones (e.g., 1-testosterone,
methenolone, stenbolone, and methyl-1-testosterone), and possibly as broadly as nonaromatizable androgens.

 

[Klimmzugernie]

I think the assessment is problematic for our purposes. the study cited was carried out a) on rats and b) only on female rats.

b) is the bigger problem with THIS topic. Endocrinology is the opposite between men and women.
Similar to dhea. Androgen in women, estrogen and gestagen properties in men.
or disbetes type 2 due to sex hormones. Estradiol increases the risk of diabetes in men and reduces it in women. --> Metformin for PCOS treatment.

I'm not saying that the study cited here can't be applied to men, but I would urge caution.

I couldn't see a real effect of Dht on estradiol levels.

 

[Type-IIx]

I think the assessment is problematic for our purposes. the study cited was carried out a) on rats and b) only on female rats.

b) is the bigger problem with THIS topic. Endocrinology is the opposite between men and women.
Similar to dhea. Androgen in women, estrogen and gestagen properties in men.
or disbetes type 2 due to sex hormones. Estradiol increases the risk of diabetes in men and reduces it in women. --> Metformin for PCOS treatment.

I'm not saying that the study cited here can't be applied to men, but I would urge caution.

I couldn't see a real effect of Dht on estradiol levels.

Whatever about female rats, it was literally carried out in ovarian granulosa cells, that men do not possess.

The fact of the matter is that this is a study of mechanistic action of aromatase rather than an assessment of biological effects intended to be extrapolated to man.

For that purpose, it is good.

But understand what it tells us: aromatase is competitively inhibited by 5α-reduced androgens. This is a relevant finding.

Nobody here is claiming that these results from granulosa cells can be used to predict the degree to which you might experience antiaromatase action of some drug.

Rather, they illustrate a common mechanism (competitive inhibition of aromatase).

Don't fall into the snare of attempting to make facile criticisms of mechanistic data because you didn't see a change in your own blood levels of estrogens under some attenuated, seemingly similar, circumstances.

For an explanation as to why your own bloodwork measures did not ostensibly reflect antiaromatase/antiestrogenic activity, consider the distinction between endocrinology & intracrinology discussed here, in the section titled Limitations of Circulating Levels as an Index of Tissue-Specific Estrogen Regulation:

Primobolan / Equipoise Crashed my E2 – Help!

Understand the complex interaction of Primobolan and Equipoise with estrogen levels, symptoms of low estrogens, and practical decision-making strategies for managing these effects in AAS users.

thinksteroids.com