Dihydrotestosterone biosynthesis

Fig. 9. Abbreviated steroid biosynthesis where DHEA = dehydroepiandrosterone and DHT = dihydrotestosterone.

Testosterone (T), the male hormone par excellence, is primarily produced in the testis. It is metabolized to the more potent dihydrotestosterone (DHT). Physiological T concentrations reflect the balance between biosynthesis and metabolism. Therefore, T is a prime... 

FIGURE 12.1 Biosynthesis of estrogens. Abbreviations DHEA, dehydroepiandrosterone El, estrone E2, estradiol T, testosterone DHT, dihydrotestosterone. Letrozole is an aroma-tase inhibitor, Finasteride is a 5a-reductase inhibitor. Androstane-3p,17P-diol (SPO) is an estrogenic steroid and its synthesis is blocked by 5a-reductase inhibitor, but not affected by aromatase inhibitor."... 

Biosynthesis of testosterone. The primary precursor is acetyl-CoA, and biosynthesis proceeds via cholesterol (see Terpenes, Steroids). Testes and adrenal cortex also utilize cholesterol which they receive as cholesterol esters from plasma lipoproteins (see Lipoproteins). A second androgen, more potent than testosterone, is 5a-dihydrotestosterone this is formed from circulating testosterone at peripheral sites, and not by the Leydig cells of the testes. Ring A of 5a-testosterone cannot be aromatized, so this hormone cannot serve as an estrogen precursor. 

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