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Chapter 4



Table of Contents

Androgens: How Vital Are They?

About 95% of androgens are synthesized in the testes, while only 5% is produced by the adrenals. The pituitary gland's signal carrier known as luteinizing hormone (LH) is responsible for the release and control of androgens by the testes. Once the pituitary gland itself is stimulated by the hyphothalamic luteinizing hormone-releasing hormone (LHRH), LH is released from it into the bloodstream, in turn LH signals the testes to produce Androgens. As previously mentioned, testosterone and other androgens play an important function in the development of an organism, but just how vital are these hormones to the human body?

As you will learn from reading the following chapters, these androgens are inter-connected; their functions, development, and metabolism are generally dependent on one another.

Types of Androgens

  • Dehydroepiandrosterone or DHEA is a natural steroid prohormone which is produced from cholesterol by the adrenal glands, the gonads, adipose tissue, brain and in the skin. This is considered as the most abundant steroid produced by the adrenal cortex. This androgen is metabolized by enzymes into androstenedione, which can undergo further chemical reactions to produce the androgen testosterone and the estrogens estrone and estradiol. DHEA is also a potent sigma-1 agonist, which means that it is a transmembrane protein. It is involved in various body functions and conditions such as cardiovascular function, schizophrenia, clinical depression, and cocaine abuse effects. In women, DHEA helps in the modulating of the immune system, especially in the post-menopausal population.
  • Androstenedione (4-androstenedione) is a 19-carbon steroid hormone produced in the adrenal glands and the gonads. Its most notable role is being the precursor of male and female sex hormones, specifically metabolized into testosterone and the estrogens like estrone and estradiol.
  • Androstenediol refers to two different steroids, with molecular weights of 290.44. They are 4-androstenediol (4-androstene-3beta, 17beta-diol) and 5-androstenediol (5-androstene-3beta, 17beta-diol). The basic difference between these two is that 4-andro is comparatively more androgenic than 5-andro. The 5-andro is the direct metabolite DHEA.
  • Androsterone (ADT) is a steroid hormone with minimal androgenic activity. It is made in the liver from the metabolism of testosterone. This hormone is said to influence human behavior, but there is no scientific evidence supporting this claim.
  • Dihydrotestosterone (5a-Dihydrotestosterone or androstanolone) or DHT for short is a metabolite of testosterone and is principally produced in the prostate gland, testes, hair follicles, and adrenal glands by 5a-reductase enzyme. DHT is responsible for the development and maintenance of male characteristics (virilization) and is vital in the reduction of estrogen-related side effects in men.
  • Testosterone is, perhaps, the most commonly known if the androgens, and it has become a household term because it is used interchangeably and sometimes synonymously with anabolic-androgenic steroids (AAS).

    This hormone occupies the top of the list when it comes to male sex hormones or androgens. This is because of testosterone's crucial part in the physical and sexual development of humans, particularly the male population.

    Testosterone main functions:

    • Development and maintenance of the male sexual characteristics.
    • Development of male reproductive organs.
    • Sperm production.
    • Growth of muscle mass and strength as well as promotion of bone density and strength (anabolic effects).

In men testosterone is principally produced in the adrenal glands and the testes. Testosterone is also biologically present in women, and is produced in the adrenal glands and the ovaries. In men, the daily production of this hormone averages between 4 and 10 milligrams; and adult men have about 20 (some estimates put the figure to about forty to sixty) times more testosterone than women. However, women are reportedly more sensitive to this hormone than men.

If testosterone is a male sex hormone, why is it present in females? There are continuing studies about the exact role of testosterone in women; however, there is a consensus in the scientific community that this hormone helps maintain skeletal and muscle strength, and is a contributing factor to women's sex drive.

There are countless testosterone theories, and one of the interesting ones is about the length of the ring finger. Some scientists have this belief that the ratio of index finger to ring finger is indicative of how much testosterone humans are exposed to during gestation in the mother's womb.

According to this ratio, higher testosterone exposure is thought to lead to a longer ring finger, which can be determined as early as 14 weeks into a pregnancy. In general, women's index and ring fingers are almost equal in length because they are exposed to less testosterone. In men, the ring finger tends to be longer because they have higher testosterone levels. Exposure of women to more testosterone can result to more 'masculine hands', i.e. longer ring fingers.

Some aspects of human behavior can also be attributed to testosterone. Research has found out that individuals with higher testosterone levels tend to drive harder bargain and therefore are considered assertive. Further, testosterone correlates with competitiveness as well as risk taking.

Androgens in the Development of the Human Body

In humans, the embryos of both sexes develop in similar fashion until the 7th week of gestation. This means that during the development of mammalian organisms the gonads, at the early stage, are capable of becoming either of the two reproductive systems – the testes or the ovaries. As early as the 4th week, the basic structures of the gonad are already present in the urogenital system. At the 6th week, epithelial sex cords grow within the evolving testes and incorporate the germ cells. The germ cells are involved in the reproduction in organisms, and in humans they are called gametes. When occurring in females, these sex cells are called ova; in males, they are commonly referred to as sperm. During the sexual differentiation, the sex cords in males become the testis cords while in females they become the cortical cords.

The epithelial cells of the sex cords in developing testes become the Sertoli cells; the Sertoli cells eventually promote sperm cell formation. By 8th week of fetal development, non-epithelial cells appear between the tubules and these cells are called the Leydig cells. After differentiation, Leydig cells do their job by producing androgens.

At this stage, the androgens function as paracrine hormones, a necessary requirement by the Sertoli cells to support sperm production. Simply put, androgens as paracrines act as 'signals' telling the Sertoli cells that the target cell is close by. Further, they are an indispensable requirement for the development of the male fetus, including the formation of the penis and scrotum. Under the continuing work of androgens, particularly testosterone, the Wolffian tubes are converted to epididymis, vas deferens, and seminal vesicles. While DHT, in turn, induces the formation of the male urethra, prostate, and the male external genitalia. With a working partnership with the Anti-Mullerian hormone (AMH), androgens prevent an anomalous occurrence – the development of female reproductive systems, such as fallopian tubes and uterus, in male embryos.

At 11th - 12th week, the embryo is capable of producing LH. At around this stage also the human chorionic gonadotrophin (HCG) starts to promote the differentiation of Leydig cells and their production of androgens.

During puberty the production of androgens, LH and follicle-stimulating hormone (FSH) is significantly increased. FSH and LH work hand in hand in reproduction. In women, FSH promotes the growth of immature Graafian follicles in the ovary. In males, FSH is vital for spermatogenesis. Throughout adulthood, FSH and androgens continually act on the Sertoli cells to maintain sperm production.

Other important functions of androgens are as follows:

  • Mitigate fat deposits. Androgens prevent accumulation of fat deposits in the body. Studies have reported that androgens disable fat cells from storing lipids.
  • Proliferate cell for muscle growth. Androgens also regulate cell proliferation and development. This is best illustrated in the development of the prostate in males. After birth, the prostate glands remain small until the start of puberty. It is during this stage that the prostate undergoes cell proliferation and acquires adult size; it is also during puberty that an increase of circulating androgens is observed. Upon adulthood, there occurs a balance between cell death and proliferation, thus discouraging further prostate growth. This is also basically the same process in the growth of skeletal muscle cells.
  • Influence sexual and psychological behavior. Circulating levels of androgens also have an impact on psychosexual processes of humans as attested by animal studies. Some neurons are sensitive to androgens and, as such, androgen levels are reportedly involved in cases of human aggression and sexual drive. A classic example of the role of androgens in sexual functioning of mammals is the occurrence of hypogonadism in human males.

Types of Steroids

There are different types of steroids based on the following two parameters – types of steroids according to medical definitions and types according to the form of administration.

Based on medical definitions of what steroids are, you can categorize these drugs in many different groups, including corticosteroids, anabolic, and androgenic.

Corticosteroids, or cortico, are man-made steroids that mimic the activity of cortisone. They are used to treat inflammation as may be caused by injury or allergy, Conditions treated with cortico include asthma, eczema, allergies, and arthritis.

The word 'anabolic' is from the Greek word 'to build up'. Thus, anabolic steroids are drugs aimed at building up muscle bulk and strength. The term “anabolic-androgenic steroids” is a more preferred term nowadays, but if you want to be technical about it, there is a difference between anabolic and androgenic steroids. It stems from the more dominant effect of these compounds. Anabolism affects growth occurring in your body's non-reproductive tract tissues. These include the skeletal muscles, bones, the larynx and vocal cords. Meanwhile, androgenic steroids effects are observed in the growth of the male reproductive tract and the development of male secondary sexual characteristics. The large muscle mass in males is due to the nitrogen-retaining effects of androgen.

Specific anabolic effects: increased muscle mass, reduction of body fats, increase in electrolyte retention, increased calcium deposits in bones, increased protein synthesis among others. Deca Durabolin is categorized as an anabolic because it has strong anabolic effects, but with only moderate androgenic reactions.

Specific androgenic effects: increase in oil production by the skin, growth of prostate tissues, reduction of fat deposits, and faster recuperation. Halotestin is of the androgenic category.

It is of important note here that the anabolic-androgenic balance is inherent in the molecular structure of these compounds. To date, there is no one drug which has been synthesized to be either fully anabolic or totally androgenic.

Steroids could be further classified according to routes of administration such as orals, injectables, sub-lingual (under the tongue), transdermal (lotion cream), and inhalants. AAS are of the first three types.

Oral steroids usually come in pill form. Newbies in the Anabolic Steroid world generally experiment with orals first primarily because they are more convenient to store and use. For professional athletes, orals make detection test easier to pass since, compared to injectables, they do not remain in the body that long. This is also why many professional athletes opt for orals if a drug test is likely to be carried out. The downside of orals is that users are at risk of liver damage because they are aplha-alkylated. Caution is always advised with oral users. Winstrol and Anadrol 50 are examples of orals.

Testosterone and its diversified analogues, when taken orally, have low oral bioavailability, i.e. the degree to which or rate at which a drug or other substance is absorbed or becomes available at the site of physiological activity after administration. Thus, for more effective and safer use most are formulated for intramuscular administration.

Athletes using injectable steroids take them once or twice a week, and inject into muscle tissue - not into the veins. The safest areas of the body to inject are the gluteus musc