Hormones, steroid source concentrations

Again, the answer should be fairly obvious. The potential therapeutic value of the steroid hormones makes these of tremendous commercial value. The commercial market for these is of the order of hundreds of millions of dollars per year. There is no comparable market for sterols and bile salts. We are faced with the interesting situation, therefore, that sterols are relatively abundant in natural sources but of relatively low commercial value, whilst steroids occur naturally at very low concentrations but are of great commercial value. Although there are tremendous variations amongst different products, steroids with desirable properties command market prices that are (ten to one thousand fold) greater than their sterol counterparts. 

Testosterone, the major androgenic hormone, accounts for 95% of the androgen concentration. The primary source of testosterone is the testes however, 3% to 5% of the testosterone concentration is derived from direct adrenal cortical secretion of testosterone or C-19 steroids such as androstenedione.17,18... 

Steroids are very powerful hormones and therefore are present in animals in only extremely minute concentrations. They are difficult to obtain from natural sources. For example, 4 tons of sow ovaries (from 80,000 pigs) were required to isolate the 12 mg of estrogen that was used for the determination of its structure. Syntheses of most of these hormones have been accomplished from simple starting materials in the laboratory. Although these routes are too long and complex to provide a practical source of... 

I) Consider three structurally similar Cis steroids —testosterone, an-drostenedione, and dehydroepiandrosterone. Each of these compounds is secreted into the blood stream by glands, and after provoking its biochemical effect, is metabolized and excreted. If the only source of the plasma pool were provided by the glandular secretion of the hormone, then the secretion rate would be used to calculate the plasma concentration. However, the picture in the case of the three Ci steroids is complicated by the fact that the three compounds are peripherally interconvertible. Since both glandular secretion and peripheral conversion of precursors contribute to the plasma pool, the production rate is used to... 

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