Androstenedione Androsterone

Sex Hormones Testosterone and androsterone are the two most important male sex hormones, or androgens. Androgens are responsible for the development of male secondary sex characteristics during puberty and for promoting tissue and muscle growth. Both are synthesized in the testes from cholesterol. Androstenedione is another minor hormone that has received particular attention because of its use by prominent athletes. 

Fig. 29.13 GC-MS chromatogram of neutral steroids in meat. Androgens (fortified, 0.2-0.5 ppb) 1, a-androsterone 2, dehydroepiandrosterone 3, epitestosterone 4, dihydrotestosterone 5, androstenedione 6, testosterone IS, methyltestosterone. Progestagens (fortified) 7,7a, pregnenolone (2.1 ppb) 8, progesterone (0.4 ppb) 9, hydroxyprogesterone (0.3 ppb). (Reprinted from Ref. 452, with permission from Elsevier Science.)...

Dehydroepiandrosterone (DHEA) is a precursor hormone secreted by the adrenal cortex and to a lesser extent by the central nervous system (Chapter 40 The Gonadal Hormones Inhibitors). It is readily converted to androstenedione, testosterone, and androsterone. In peripheral tissues, aromatase converts DHEA to estradiol. In the plasma, DHEA is converted to DHEA sulfate (DHEAS). 

Overall, other adrenal androgens also show a progressive decrease in urinary excretion in both men and women. Thus, the mean 17-ketosteroid urine levels of elderly people are about 50% of those in young adults. This is primarily secondary to decreased dehydroepiandrosterone (DHEA) and androsterone production. In men, about one-third of the daily 17-ketosteroids are of testicular origen, the remainder being mainly from the adrenals. Androstenedione is a prehormone for testosterone. 

Androsterone and 5)3-androsterone, which are the major metabolites, were thought to be uniquely derived from the plasma androstenedione pool. Korenman et al. [170,388] demonstrated by the double isotope tracer method using carbon-14-labeled testosterone and tritium-labeled androstenedione that neither androsterone nor 5 -androsterone is a unique metabolite of a plasma androstenedione pool. A unique steroid metabolite has been defined by Dorfman [326] as a steroid persisting or formed during metabolism which can be related to one and only one tissue steroid. Korenman et al. obtained different tritium/carbon-14 ratios for androsterone and 5/3-androsterone, suggesting that other pathways of testosterone and androstenedione metabolism also exist. These other pathways, possibly metabolism of testosterone and androstenedione by peripheral tissue, may be responsible for the relative enrichment of either the 5a- or the 5/8-isomer of the urinary metabolites [305]. 

Adrenal androgens also have a complex metabolic fate DHEA-S is formed in the adrenal cortex or by sulfokinases in the liver and kidney from DHEA and excreted by the kidney. DHEA and DHEA-S can be metabolized by 7a-and 16a-hydroxylases. 17p-Reduction of both compounds forms A -5-androstenediol and its sulfate. Androstenedione can be metabolized to androsterone after 3a- and 5a-reduction. 5P-Reduction results in the formation of etiocholanolone (see Eigure 51-7). These metabolites are conjugated to glucuronides and sulfates, which are then excreted in the urine. 

Ketoetiocholanolone 11/3-Hydroxy androsterone 1 l/S-Hydroxyetiocholanolone 0.4-2.0) 0.2-1.0> 0.1-0.5j Cortisol, 11/3-hydroxy-androstenedione... 

The fascicular and reticular zones of the adrenal cortex also produce andtx>gens — androstenedione. DHA (dehydroepi-androsterone) and DHA sulphate. These compounds probably owe their andro-... 

Fig. 11.6.3. HPLC separation of androgens. Chromatographic conditions column, two Partisil 5 columns in series (300 X 4.6 mm I.D.) mobile phase, dichloromethane-acetomtrile-2-propanol (179 20 1) flow rate, 0.4 ml/min temperature, ambient detection, UV at 254 nm and 280 nm. Peaks I, androstanedione, II, etiocholanedione III, androstenedione IV, epietiocholanolone V, dehydroepi-androsterone VI, epiandrosterone VII, androsterone, VIII, androstadienedione IX, testosterone, X, etiocholanolone XI, epitestosterone. Reproduced from Hunter et al.

Testosterone circulating in the blood is mainly metabolized in the liver to androstenedione which is converted via intermediates into androsterone and its 3 isomer. These are then excreted in urine as glucuro-nides or sulfate conjugates. 

Androstanolone, androstenedione, androsteno-lone, androsterone see androgens. 

Androgens a group of male gonadal hormones, including testosterone, androsterone and androsteno-lone, which are formed in the intermediary cells of the testes tissue, and a number of less active A. produced in the adrenal cortex, e.g. androstenedione and adrenosterone (Fig.). Since A. are precursors of Estrogens (see), they are also synthesized in the ovaries and fetoplacental unit. At present more than 30 naturally occurring A. are known, all structurally related to the parent hydrocarbon, androstane (see Steroids). 

Androsterone, 3a-kydroxy-Sa-androstan-I7-one an androgen, Af, 290.5, formed in the interstitial cells of the testes. Its androgenic activity is 7 times weaker than that of testosterone. It is biosynthesized from progesterone via 17a-hydroxyprogesterone and androstenedione. A. was first isolate by Butenandt in 1931 from human urine (IS mg A. from 15,0001 urine). 

List of abbreviations and trivial names. Dehydroepiandrosterone (DHA, D), 3/J-hydroxyandrost-5-en-17-one androstenediol (A°-diol, A ), androsta-5-en-3/S, 17 -diol androstenetriol (triol), androsta-5-en-3, 16o, 17 -triol androsterone (A), 3ot-hy-droxy-5a-androstan-17-one 5/S-androsterone (5fiA), 3a-hydroxy-5/3-androstan-17-one epiandrosterone, 3/3-hydroKy-5o-androstan-17-one androstanediol (Adiol), 5a-and-rostan-3a, 17/S-diol 3/S-androstanediol, 5a-androstan-3/9, 17/3-diol 5/3-androstanediol (5 Adiol), 5/S-androstan-3a, 17 -diol androstenedione (A ), androsta-4-en-3, 17,... 

---