Boldenone & Erythropoiesis

Boldenone & Erythropoiesis
5-a & 5-b isomers actions related to erythropoiesis

by Blackbaccara

This review is a working hypothesis and not a demonstration of the superiority of boldenone over the other AAS in regard of erythropoiesis.

Boldenone (17beta Hydroxyandrosta-1,4-dien-3-one) is often believe in the bodybuilding community to be a potent erythropoiesis stimulant able to enhance blood parameters by increasing red cells and thus enhancing the oxygen-carrying capacity of blood.

But actually, we know that virtually all AAS* (1) can enhance erythropoietin, like nandrolone decanoate (deca-durabolin) (2) which has been estimated as potent as recombinant human erythropoietin in the treatment of anemia (3).

Furthermore, the US food and drug administration has approved oxymetholone, an anabolic-androgenic steroid sold under the name Anadrol50, for the treatment of anemia. However this compound is maybe not the most potent for increasing erythropoietin at supraphysiological level and this could be related to its weak androgenicity (4).

Effects on erythropoietin and erythropoiesis are thought to be mediated through the AR since androgen receptors have been localized in bone marrow (5) and kidneys (6).

But inactive androgens known as 5-b isomers (7) have been shown to be very effective in regards to erythropoiesis. These steroids result of the reduction of the 4,5 double bond by the enzyme 5-b reductase. They differ from usual 5-a reducted metabolites by the position of the hydrogen atom at the rings A and B junction.

A study on mices shows that 5 alpha-androstane and 5 beta-androstane metabolites have nearly the same efficacy in the treatment of aplastic anemia (8) but « 5 beta-androstanes were more efficient on the granulopoietic committed stem cells ».
If AAS and their 5-alpha structures or metabolites work predominantly by stimulating erythropoietin release, and the other hand, anti-erythropeietin doesn’t abolish the erythropoiesis-stimulating effects of 5-beta steroids (9). The exact mechanism of action of these metabolites is unkwnon and many hypothesis co-exist like a direct influence of these steroids on blood-forming tissues and an enhancing effect on heme synthesis. It as also been demonstrated that the nonandrogenic 5-b dihydrotestosterone provides some protective effect on erythroid precursor cells (10) and while testosterone and 5-a metabolites are unable to enhance the number of colonies of hemoglobin synthesizing cells, 5-b metabolites are very active in this regard. (11).
So it is established that 5-b androstanes are potent and more effectives than 5-a androstanes to stimulate erythropoiesis. (12)

Now let back to boldenone. The compound doesn’t undergo 5-a reduction but as we can see the compound is extensively 5-b reducted since its main metabolites have this structure and recent analysis have confirmed this metabolic pathway(13). Actually the real potency of 5-b dihydroboldenone (5 beta-androst-1-en-17 beta-ol-3-one) and its derivatives to increase erythropoeisis is unknown but in respect of researches on a large panel of 5-b androstane steroids we can figure that this effect is structure-related and that boldenone metabolites could be potent stimulators of erythropoiesis.

Finally because testosterone analogs and 5-a DHT derivatives seem to act mostly on this topic by increasing EPO release, a synergic effect with 5-b DHT derivatives could be expected. And boldenone as a precursor of 5-b metabolites in association with a 5-a derivative or precursor could be a good combo to improve blood parameters.

* Anabolic-androgenic steroids
(1) Effects of androgenic-anabolic steroids in athletes.
(2) Evolution of serum erythropoietin after androgen administration to hemodialysis patients.
(3) Androgen versus erythropoietin for the treatment of anemia in hemodialyzed patients.
(4) Inability of oxymetholone to elicit an erythropoietin-hypersecretory state in orchidectomised male mice.
(5) Localization of androgen receptor expression in human bone marrow
(6) Immunohistochemical localization of androgen receptors with mono- and polyclonal antibodies to androgen receptor.
(7) Julius A. Vida Androgens and anabolic agents.
(8) A study of the efficacy of 5 alpha- and 5 beta-androstanes in chronic experimental aplastic anemia in mice.
(9) Stimulation of Mammalian Erythropoiesis by 5b-H Steroid Metabolites
(10) Protective effect of testosterone of 5?-dihydrotestosterone pretreatment on CFU-E numbers in busulfan-treated rabbits.
(11) Steroids and hematopoiesis, the effect of steroids on in vitro erythroid colony growth.
(12) The influence of steroid hormone metabolites on the in vitro development of erythroid colonies derived from human bone marrow.
(13) ) Metabolism of boldenone in man: gas chromatographic/mass spectrometric identification of urinary excreted metabolites and determination of excretion rates.