Testosterone – Basic Introduction.

For males with Kallmann syndrome a major symptom is hypogonadism or a deficiency in the production of the hormone testosterone.

Primary hypogonadism can occur at any age in males as a result of a number of different factors including age, infection or physical damage. In primary hypogonadism the testes were functional at one stage but cease to function correctly at some point during life.

Males with Kallmann syndrome and other forms of hypogonadotrophic hypogonadism (HH) normally have secondary hypogonadism. In secondary hypogonadism the testes are functional but dormant. The lack of hormone signals from the pituitary gland in the form of LH and FSH prevents the testes from working correctly and producing testosterone and sperm. The testes remain in their pre-pubertal size and shape as they have never received the correct signals from the pituitary gland.

Testosterone is the primary “male” hormone.

Testosterone can be classed as a pro-hormone as it is broken down in the body into two other active hormones which work along side testosterone.

17-beta-oestradiol
5-alpha-dihydrotestosterone

These three hormones work in combination or on their own to produce a wide range of effects around the body. While testosterone itself is not a vital hormone for life, its absence can induce a wide range of symptoms around the body and it is essential for the body to become “male”.

Testosterone has different effects on the body which are age related.

1. During development as an embryo testosterone is essential for sexual differentiation into a male. All humans are female by default, it is the testosterone produced as an embryo which causes the male physical development. Any disruption in the amount of testosterone effect in a male embryo can cause problems in the physical development of the male genitalia.

2. During puberty testosterone is essential for virilisation into adulthood.

3. During adulthood testosterone is required for maintaining virilisation, sexual function, muscle development and bone strength.

Biological effects of testosterone:

Is essential for bone density and strength

Stimulates red cell production by the bone marrow which increases energy levels

Has an anabolic effect on the muscles, allows men to build muscle block.

Influences the brain to induce the libido effect

Helps liver function with increased enzyme activity and protein synthesis

Stimulates growth & function of prostate gland

In very early stages of development causes the masculinisation of the genitalia and allows for growth of penis & scrotum at the time of puberty

Causes the larynx to grow, lengthening the vocal cords

Stimulates body and facial hair production while sometimes reducing head hair production