Androgenic substances

The primary function of AC. TH is the stimulation of the adrenal cortex to produce its hormones, which have already been discussed. This is evideni from the therapeutic effect of administration of ACTH. which is closely similar to that of Ihese hormones, so that if ihe action of only one of them is sought, its administration is preferable, Moreover. ACTH stimulates secretion of the androgenic substances mentioned as produced by the adrenal cortex. 

The adrenocorticotrophic hormone ACTH (corticotropin) stimulates the adrenal cortex to secrete the glucocorticoids hydrocortisone (cortisol) and corticosterone, the mineralocorticoid aldosterone, and a number of weakly androgenic substances, as well as a small amount of testosterone. Aldosterone synthesis is also regulated by renin and angiotensin. 

Androgens are masculinizing substances. The endogenous male gonadal hormone is the steroid testosterone from the interstitial Leydig cells of the testis. 

The Tier 2 testing assays are intended to confirm, characterize, and quantify effects for estrogen, androgen, and thyroid active substances. The EDSTAC selected Tier 2 to include the most sensitive developmental Ufestage, to identify the specific hazard caused by the chemical and establish a dose-response relationship, and to include a range of taxa. The Tier 2 screening assays under consideration by the US-EPA are summarized in Table 4.22. 

Certain medicines may not be imported under the personal importation provisions, including drugs of abuse, such as narcotics, amphetamines and psychotropic substances, and anabolic substances, androgenic steroids and treatments for alcohol and drug addiction. There are also controls over certain other medicines including erythropoietin, growth hormones and gonadotrophins. 

Androgens are substances which cause development of secondary sex characters in males. The most important androgen secreted by testes is testosterone. Testosterone is synthesized from the cholesterol in testes mainly, under the influence of LH from pituitary. In peripheral tissues testosterone is partly converted into more active dihydrotestosterone. 

Drugs that may inhibit cytochrome P450 metabolism of other drugs include amiodarone, androgens, atazanavir, chloramphenicol, cimetidine, ciprofloxacin, clarithromycin, cyclosporine, delavirdine, diltiazem, diphenhydramine, disulfiram, enoxacin, erythromycin, fluconazole, fluoxetine, fluvoxamine, furanocoumarins (substances in grapefruit juice), indinavir, isoniazid, itraconazole, ketoconazole, metronidazole, mexile-tine, miconazole, nefazodone, omeprazole, paroxetine, propoxyphene, quinidine, ritonavir, sulfamethizole, verapamil, voriconazole, zafirlukast, and zileuton. 

The decreased level of androgens in castrated male cattle as a result of testicular removal leads to production of a carcass that is intermediate between that of an intact male and a female. Since the increased proportion of fat in such a carcass makes it less valuable for the health-conscious consumer, extensive research has been directed towards replacing the loss of carcass quality resulting from castration, by administration to the animals of various natural and synthetic hormonal substances, collectively called anabolic hormonal-type growth promoters. These compounds can substantially increase growth rate and improve feed efficiency and carcass composition in a process that may be highly profitable for the animal feeders. 

In November, 1985, the Commission submitted to the Council a draft regulation that would ban natural hormones, except for therapeutic purposes, and banned synthetic hormones altogether. In December, 1985, the Commission s proposal to amend Directive 81/602 to prohibit use of anabolics was adopted by the Council and became Council directive EC 85/649. The directive banned the use of natural hormones except for therapeutic purposes and absolutely banned the use of synthetic hormones. The directive also imposed a trade clause that required Member States to prohibit importation from third countries of live animals and of meat from animals to which have been administered in any way whatever substances with a thyreostatic, estrogenic, androgenic, or gestagenic action. Member States were required to bring this directive into force no later than January 1, 1988. 

Female Hormones. Closely related 10 the male androgenic hormones, and probably synthesized from them in the female organism, are the estrogenic hormones which are produced principally in the ovary. Although / -estradiol is die normally secreted ovarian hormone, a number or ulher estrogenic substances have been isolated from urine and from animal studies. They include o-cstradiol. esiriol, and estrone. The structures of these hormones are given in Fig. 2. 

The ability of androgens to counter osteoporosis is the basis of their use as a supplement to estrogens in one version of hormone replacement therapy. Testosterone can increase markers of bone formation (66). However, the early closure of epiphyses, with an arrest of growth, is a risk if children are exposed to these substances this latter effect may be produced by the estrogen to which testosterone is metabolized. In some patients with... 

There is a persistent illegal market in androgenic anabolic steroids, to promote physical strength. A difficulty in determining the ultimate consequences of anabolic steroid abuse for body-building or to advance sporting achievement is that individuals who are susceptible to such abuse may well have taken several different types of substance at the same time or in succession. Indeed, an... 

The enlargement of individual muscle cells and muscle fibers via elevated protein synthesis caused by anabolic substances. This is the first growth mechanism and its called hypertrophy. Androgens such as testosterone (endogenous or exogenous) and all AAS have the greatest effect at this level. 

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