Testosterone precursors

Foster ZJ, Housner JA. Anabolic-androgenic steroids and testosterone precursors ergogenic aids and sport. Curr Sports Med Rep. 2004 3 234-241. 

The tissue content of the testis can be analysed by a several methods for androgens, either by a high-performance liquid chromatography (HPLC), or by specific radioimmunoassays for testosterone, progesterone, and the testosterone precursors in the biosynthetic pathway. 

C. Gilligan, C. Passmore, Intravaginal drug delivery devices f the administration of testosterone and testosterone precursors, WO Patent App. PCT/IE1998/000,1998. 

Protecting groups, as described in the text, are essential parts of many organic syntheses. An example is the synthesis of the sex hormone testosterone (Section 4-7) from a cholesterol-derived starting material. Natural sources of steroid hormones are far too limited to meet the needs of medicine and research these molecules must be synthesized. In our case, the hydroxy function at C3 and carbonyl function at C17 of the starting mat al have to trade places to furnish the desired testosterone precursor. In other words, selective reduction of the carbonyl group at C17 and oxidation of the hydroxy group at C3 are required. In the scheme that was... 

Testosterone promotes muscle growth deepening of the voice the growth of body hair and other male secondary sex characteristics Testosterone is formed from cholesterol and IS the biosynthetic precursor of estradiol the principal female sex hormone or estrogen Estradiol is a key substance m the regulation of the menstrual cycle and the reproductive process It is the hormone most responsible for the development of female secondary sex characteristics... 

FIGURE 25.43 The steroid hormones are synthesized from cholesterol, with intermediate formation of pregnenolone and progesterone. Testosterone, the principal male sex hormone steroid, is a precursor to /3-estradiol. Cortisol, a glucocorticoid, and aldosterone, a mineralocorticoid, are also derived from progesterone. 

Testosterone is also produced primarily in the ovaries (and in much smaller amounts in the adrenal glands) of females as a precursor for the estrogens. /3-Estradiol is the most important estrogen (Eigure 25.43). 

The ceUular source of the various ovarian steroids has been difficult to unravel, but a transfer of substrates between two cell types is involved. Theca cells are the source of androstenedione and testosterone. These are converted by the aromatase enzyme in granulosa cells to estrone and estradiol, respectively. Progesterone, a precursor for all steroid hormones, is produced and secreted by the corpus luteum as an end-product hormone because these cells do not contain the enzymes necessary to convert progesterone ro other steroid hormones (Figure 42-8). 

Cholesterol is the biochemical precursor of cortisone, estradiol, and testosterone. 

DHEA is an adrenal hormone that is a precursor to the sex hormones testosterone and estrogen, as well as other hormones. DHEA is reported to increase testosterone and decrease total body fat, and also to have anabolic and anti-aging effects. The... 

The androgens and oestrogens represent the major male and female sex hormones respectively (Figure 11.B3). The testicular Leydig cells represent the primary source of androgens in the male, of which testosterone is the major one. Testosterone, in turn, serves as a precursor for two additional steroids, i.e. dihydrotestosterone and the oestrogen called oestradiol. These mediate many of its biological effects. 

Testosterone represents the immediate precursor of the oestrogens, the conversion being catalysed by the aromatase complex, i.e. a microsomal enzyme system. The biological actions of oestrogens may be summarized as ... 

The follicular phase covers the development of the follicle, which involves an increase in its size due to an increase in follicular fluid, growth of the ovum (i.e. an increase in the contents of RNA and protein) and an increase in the number of cells that surround the ovum. These cells are of two types, the granulosa and the thecal cells. The role of these cells is to synthesise and secrete the steroid hormones oestrogens (mainly oestradiol). The precursor molecule for their synthesis is cholesterol. There is a division of labour between these cells the thecal cells convert cholesterol into the male sex hormones androstenedione and testosterone, which are released into the blood to be taken up by the granulosa cells where they are converted to the oestrogens (Figure 19.8). For details of pathways, see Appendix 19.1. 

The advantage of this division of labour is not obvious but one possibility is that secretion of testosterone by the cells not only provides a precursor for oestradiol but provides a hormone that is secreted into the bloodstream to influence, perhaps surprisingly, sexual activity in women, particularly sexual arousal and interest. 

The formation of what as a principal precursor of testosterone is considered the biosynthetic rate-limiting step ... 

Brown, G. A., M. D. Vukovich, T. A. Reifenrath, et al. Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men. Int J... 

---