Testosterone aromatization

A direct, one-step aromatization of 19-substituted steroids has appeared in the Hterature, ie, cholesterol (3), dehydroisoandrosterone, androsterone, progesterone (1), and testosterone react with an electrophilic mthenium complex, C Ru , where Cp represents Tj -cyclopentadienyl, obtained through protonation of [Cp Ru(OCH2)]2 using triflic acid, to provide estrone (20) directly (46). 

The most significant metabolic product of testosterone is DHT, since in many tissues, including prostate, external genitalia, and some areas of the skin, this is the active form of the hormone. The plasma content of DHT in the adult male is about one-tenth that of testosterone, and approximately 400 ig of DHT is produced daily as compared with about 5 mg of testosterone. About 50-100 ig of DHT are secreted by the testes. The rest is produced peripherally from testosterone in a reaction catalyzed by the NADPH-depen-dent 5oi-reductase (Figure 42-6). Testosterone can thus be considered a prohormone, since it is converted into a much more potent compound (dihydrotestosterone) and since most of this conversion occurs outside the testes. Some estradiol is formed from the peripheral aromatization of testosterone, particularly in males. 

Estrogens are formed by the aromatization of androgens in a complex process that involves three hydroxyla-tion steps, each of which requires O2 and NADPH. The aromatase enzyme complex is thought to include a P450 monooxygenase. Estradiol is formed if the substrate of this enzyme complex is testosterone, whereas estrone results from the aromatization of androstenedione. 

Significant amounts of estrogens are produced by the peripheral aromatization of androgens. In human males, the peripheral aromatization of testosterone to estradiol (Ej) accounts for 80% of the production of the latter. In females, adrenal androgens are important... 

Mobus E, M Jahn, R Schmid, D Jahn, E Maser (1997) Testosterone-regulated expression of enzymes involved in steroid and aromatic hydrocarbon catabolism in Comamonas testosteroni. J Bacteriol 179 5951-5955. 

The brain, like the seminal vesicles, is able to reduce testosterone to 5a-dihydrotestosterone (DHT) and, like the placenta, the brain aromatizes testosterone to estradiol (Fig. 52-4). Neither conversion occurs equally in all brain regions. The aromatization reaction is discussed below. Regional distribution of 5a-reductase activity toward testosterone in rat brain reveals that the highest activity is found in the midbrain and brainstem, intermediate activity is found in the hypothalamus and thalamus, and the lowest activity is found in the cerebral cortex [1]. The pituitary has higher 5a-reductase activity than any region of the brain, and its activity is subject to changes as... 

The aromatization of testosterone to form estradiol, and of androstenedione to form estrone (Fig. 52-4), has been described in brain tissue in vitro and in vivo [1, 9]. Aromatization is higher in hypothalamus and limbic... 

Replacement of the hydrophilic acrylamide by the more hydrophobic N-iso-propylacrylamide, in combination with the pre-functionalization of the capillary with (3-methacryloyloxypropyl) trimethoxysilane, afforded a monolithic gel covalently attached to the capillary wall. A substantial improvement in the separations of aromatic ketones and steroids was observed using these fritless hydrogel columns, as seen by the column efficiencies of 160,000 found for hydrocortisone and testosterone [92]. The separations exhibited many of the attributes typical of reversed-phase chromatography and led to the conclusion that, in contrast to the original polyacrylamide-based gels, size-exclusion mechanism was no longer the primary mechanism of separation. 

Estradiol 18 Follicle of ovary Placenta (in pregnancy) Aromatization of testosterone... 

The testis, like the ovary, has both gametogenic and endocrine functions. The onset of gametogenic function of the testes is controlled largely by the secretion of FSH by the pituitary. High concentrations of testosterone locally are also required for continuing sperm production in the seminiferous tubules. The Sertoli cells in the seminiferous tubules may be the source of the estradiol produced in the testes via aromatization of locally produced testosterone. With LH stimulation, testosterone is produced by the interstitial or Leydig cells found in the spaces between the seminiferous tubules. 

Cholesterol is the most common steroid of mammalian membranes. It is formed biologically from lanosterol, as shown. Ergosterol is the most common steroid of fungal membranes. It differs from cholesterol by the presence of two additional double bonds that affect its three dimensional structure. Also shown are three so-called steroid hormones, andros-terone, estradiol, and testosterone. Note the presence of an aromatic A-ring in estradiol. 

The third way testosterone affects fat synthesis is not positive. When testosterone levels are elevated, more is converted into estrogens by way of the conversion enzyme aromatase. This is called aromatization, an important word to understand before reading the rest of this book Estrogen in turn increases female pattern fat deposits and suppresses HPTA function. Atleast estrogen can increase GH production. 

Many used Winstrol (stanozolol) as a pre-contest drug because it provided a continuously harder appearance. When 50-100mg every 1-2 days was stacked with 76-mg of Parabolan every 2-3 days, the results were quite impressive. Many also added Masteron, Equipoise, or Testosterone Propionate/ Testosterone Suspension with the addition of anti-estrogens for water retention and aromatization control. 

Aromatization Yes, somewhat less than testosterone cypionate or enanthate. 

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