Citazione:Messaggio inserito da Marlin
Lo scorso anno si diceva che era perchè si dopavano col GH (ormone della crescita) che non risulta all'antidoping (ed è costosissimo).
Ora mi viene il dubbio che magari, oltre a questo, usino epitestosterone per tenere inalterato il rapporto di 6 a 1 (oltre al quale è considerato doping) tra il teststerone e il suo epimero (che sembra essere un potente anti-dht, dal momento che non si trasforma in questa sostanza dannosa per i capelli).
Molto interessante Marlin, come sempre i tuoi interventi sono illuminanti e stimolanti: Che l'epitestosterone fosse un antiandrogeno endogeno non è affatto una novità, mi meraviglia molto che l'ipotesi di un suo impiego terapeutico in terapria tricologica sia emerso così recentemente.
Spulciando articoli scientifici su PUb med ho trovato degli abstract davvero illuminanti. Bisogna credo assolutamente approfondire in materia. Si sa qualcosa delle sperimentazioni del Dott. Rossi?
Vi allego gli abstarct
Citazione:
J Invest Dermatol. 1987 Aug;89(2):209-11. Related Articles, Links
Epitestosterone: a potential new antiandrogen.
Nuck BA, Lucky AW.
Epitestosterone (EpiT) is the 17 alpha-hydroxy epimer of testosterone (T) and a natural steroid metabolite. It has previously been shown to be a 5 alpha-reductase inhibitor. We have studied EpiT as an antiandrogen using the hamster flank organ model. One-centimeter silastic capsules of crystalline T or dihydrotestosterone (DHT) were implanted subcutaneously in female Golden Syrian hamsters to provide continuous androgenic stimulation. After 3 weeks, the pigmented spot was measured and the flank organs were fixed for histologic sectioning. The maximum surface area (SA) from a central section of the sebaceous gland and the diameter of hair follicles were measured using a computerized digitizing tablet. Following T and DHT, respectively, there was a significant increase in pigmented spot size (656/382%), sebaceous gland SA (210/315%), and mean hair follicle diameter (80/56%). A 1-cm capsule of EpiT alone had no androgenic effect. Five- and ten-fold doses of EpiT were implanted with T or DHT. Epitestosterone significantly inhibited the T-dependent stimulation of pigment, sebaceous gland, and hair follicle at either 5- and/or 10-fold excess doses. Additionally, a 10-fold dose of EpiT also inhibited DHT-dependent stimulation of all 3 cutaneous structures. We conclude that EpiT was effective as an antiandrogen and had no intrinsic androgenic activity in the hamster flank organ. It probably functions both as a competitive inhibitor of the androgen receptor and as a 5 alpha-reductase inhibitor. Pigment and sebaceous gland growth were more sensitive than the hair follicle to androgen inhibition by EpiT at the time and doses tested.
Citazione:
Cas Lek Cesk. 1989 Jun 9;128(24):754-5. Related Articles, Links
[Does epitestosterone function as an endogenous antiandrogen?]
[Article in Czech]
Bicikova M, Hampl R, Starka L.
The action of the endogenous steroid epitestosterone administered to castrated male mice substituted with testosterone propionate is manifested by reduced weight increments and a reduced relative weight of their seminal vesicles and kidneys. Epitestosterone in vitro displaces androgens from their bond with receptors in cytosol from rat prostates and markedly inhibits the testosterone transformation to the more effective androgen dihydrotestosterone. Epitestosterone can be thus defined as a true endogenous antiandrogen; to its action at the receptor level a potent inhibitory effect on 5 alpha-reductase must be added.
Citazione:
J Steroid Biochem. 1989 Nov;33(5):1019-21. Related Articles, Links
Epitestosterone--an endogenous antiandrogen?
Starka L, Bicikova M, Hampl R.
Research Institute of Endocrinology, Praha, Czechoslovakia.
Epitestosterone (17 alpha-hydroxy-4-androsten-3-one), a normal constituent of human plasma and urine, prevents the testosterone induced changes in body weight and in organ weights of seminal vesicles and kidney of castrated male mice. It competes with methyltrienolone in the binding to rat prostate cytosol (Ki = 29.8 nmol.l-1. It inhibits also the activity of 5 alpha-reductase from rat prostate pellet (Ki = 1.2 mumols.l-1). Epitestosterone can be considered as a weak antiandrogen in the term of displacement of androgen from receptor binding and as an efficient inhibitor of 5 alpha-reductase.
Citazione: Sb Lek. 2001;102(1):7-11. Related Articles, Links
Antiandrogenic activity of epitestosterone in male mice in vivo.
Starka L, Broulik PD.
Inst. Endocrinology, Narodni 8, 116 94 Prague 1, Czech Republic. lstarka@endo.cz
Steroidal antiandrogen epitestosterone was administered to intact male mice and its effect on seminal vesicles, kidney, femoral bones and circulating calcium, phosphate, testosterone and LH were compared with controls and castrated animals. Epitestosterone was previously reported as an inhibitor the binding of androgens to their receptors, an inhibitor of the formation of dihydrotestosterone from testosterone and a modulator of estradiol-estrone conversion. In the present study it is demonstrated that it decreased the weight of kidney, seminal vesicles and bone density, ash weight and calcium and phosphate content of femoral bone tissue significantly, although not to the values as low as those seen in castrated animals. Thus in mice epitestosterone effects could be classified as antiandrogenic.
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