Testosterone

Testosterone Meaning: The primary sex hormone present in men is a testosterone hormone. It is in control of a man's physical appearance. Testosterone is produced by the testes (testicles). Women, like men, have testosterone, but in much smaller levels.

Testosterone Definition: Men's bodies contain a substance (hormone) that causes them to develop male physical and sexual characteristics.

Testosterone Structure

Testosterone is an androstanoid that contains 17-beta-hydroxy and 3-oxo groups, as well as C-4-C-5 unsaturation. It acts as an androgen, a human metabolite, a metabolite in Daphnia Magna, and a metabolite in mice. It's a 17-beta-hydroxysteroid, androstanoid, C19-steroid, and 3-oxo-Delta(4) steroid all rolled into one.

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Where is Testosterone Produced?

The gonads (the Leydig cells in the testes in men and the ovaries in women) produce testosterone, with minor amounts released by the adrenal glands in both sexes.

How is Testosterone Hormone Regulated?

The output of testosterone is closely regulated in order to maintain normal blood levels, though levels are normally highest in the morning and fall later. The hypothalamus and pituitary gland play an important role in regulating how much testosterone the testes release. The pituitary gland releases a luteinising hormone in response to gonadotrophin-releasing hormone from the hypothalamus, which flows through the bloodstream to the gonads and activates testosterone development and release.

When testosterone levels in the blood rise, the hypothalamus produces less gonadotrophin-releasing hormone, which suppresses the pituitary gland's development of luteinizing hormone. As a result, testosterone levels drop, negative feedback is reduced, and gonadotrophin-releasing hormone production resumes in the hypothalamus.

Testosterone Hormone Functions

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Testosterone is an Anabolic Steroid:

Testosterone is essential for the health of muscles, metabolism, and bone density. Synthetic versions can be used to boost performance. Although these medications were created to help men with low testosterone get their T levels back to normal, some people use them illegally to bulk up their muscles and gain strength quickly. This can have long-term negative effects, such as breast growth, heart attacks, and liver disease.

Testosterone Plays an Important Role in Fertility:

Testosterone levels must be in a healthy range in order to produce viable sperm. Erectile dysfunction and poor-quality erections can also be caused by low testosterone levels.

High Testosterone is Linked to Certain Personality Traits:

High testosterone levels have been related to a high rate of risk-taking. TRT focuses on getting T levels down to normal, not artificially boosting them since high testosterone levels are a predictor of anti-social personality traits in both genders.

Testosterone is involved in the physical transformation of a boy into a male. Puberty is the name given to this stage of development. The following changes have been made:

• Penis and testes development

• Hair growth on the face, pubic region, and body

• The tone of the voice becomes richer.

• Muscle development and bone strength

• Increasing  height

Testosterone Physiological Effects

Androgens like testosterone, in general, stimulate protein synthesis and thus tissue development in tissues with androgen receptors. Testosterone is known for its virilizing and anabolic properties (though these categorical descriptions are somewhat arbitrary, as there is a great deal of mutual overlap between them).

1. Anabolic Effects: Muscle mass and strength gain, increased bone density and strength, and stimulation of linear growth and bone maturation are all anabolic effects.

2. Androgenic Effects: Androgenic effects include the maturation of the sex organs in the foetus, especially the penis and the development of the scrotum, as well as a deepening of the speech, growth of facial hair (such as the beard), and axillary (underarm) hair after birth (usually at puberty). Many of these are classified as secondary sex characteristics in men.

The age at which testosterone effects are most common can also be identified. The levels and duration of circulating free testosterone are largely responsible for postnatal effects in both males and females.

Prior to Birth

Before birth, the effects are divided into two groups, each based on the stages of development.

• Around 4 to 6 weeks into the pregnancy, the first phase begins. Midline fusion, phallic urethra, scrotal thinning and rugation, and phallic enlargement are examples of genital virilization, while testosterone plays a far smaller role than dihydrotestosterone. The prostate gland and seminal vesicles are also developing.

• Androgen levels are linked to sex formation during the second trimester. Specifically, testosterone and anti-Müllerian hormone (AMH) stimulate Wolffian duct growth and Müllerian duct degeneration, respectively. This cycle has an effect on the fetus's femininization or masculinization, and it can be a better indicator of feminine or masculine behaviours like sex-typed behaviour than an adult's own levels. Prenatal androgens seem to have a mild impact on spatial skills, as well as influencing desires and participation in gendered activities. Male-typical play in childhood was linked to lower satisfaction with the female gender and lower heterosexism in women with CAH.

Early Infancy

The effects of androgens in early childhood are the least known. Testosterone levels increase in male babies during the first weeks of life. For a few months, the levels remain in the pubertal range, but by 4–7 months of age, they have normally reached the scarcely detectable levels of childhood. The purpose of this human increase is unknown. Since no major improvements have been observed in other areas of the body, it is thought that brain masculinization is taking place. The aromatization of testosterone into oestrogen, which crosses the blood-brain barrier and reaches the male brain, masculinizes the male brain, while female foetuses have -fetoprotein, which binds the oestrogen and makes female brains non-masculine.

Prior to Puberty

Both boys and girls experience the effects of increased androgen levels prior to puberty. Adult-type body odour, elevated oiliness of skin and hair, acne, pubarche (appearance of pubic hair), axillary hair (armpit hair), growth spurt, rapid bone maturation, and facial hair are only a few of the symptoms.

Puberty

When androgen levels are higher than average adult female levels for months or years, pubertal symptoms begin to appear. These are common late pubertal effects in males, and they occur in females after extended periods of elevated free testosterone levels in the blood. The following are some of the effects:

There is an increase in spermatogenic tissue in the testicles, male fertility, penis or clitoris enlargement, libido, and erection frequency, or clitoral engorgement. Human growth hormone is involved in the growth of the neck, forehead, chin, and nose, as well as the remodelling of facial bone contours. The maturation of the bones has been completed, and development has come to an end. This happens indirectly by estradiol metabolites, resulting in further grazing.

Adult

Natural sperm production requires testosterone. It triggers genes in Sertoli cells that encourage spermatogonia differentiation. Under dominance challenge, it controls the acute HPA (hypothalamic–pituitary–adrenal axis) response. Androgens, such as testosterone, promote muscle development. In humans, testosterone controls the number of thromboxane A2 receptors on megakaryocytes and platelets, as well as platelet aggregation.

Males have more clearly shown adult testosterone effects than females, but both sexes are likely to benefit. Some of these effects can fade as testosterone levels drop in the latter decades of adulthood.

What Happens if the Testosterone Levels are Too High?

The impact of too much testosterone on the body varies depending on age and gender. Adult men are unlikely to develop a condition that causes them to generate too much testosterone, and it can be difficult to tell whether a man has too much testosterone. More clearly, young children with too much testosterone can undergo a false growth spurt and display signs of Precocious puberty i.e. early puberty, and young girls may have irregular genitalia changes. Too much testosterone can trigger precocious puberty and infertility in both males and females.

High testosterone levels in the blood may also be a sign of polycystic ovary syndrome in women. Increased acne, body and facial hair (hirsutism), balding at the front of the hairline, increased muscle bulk, and a deepening voice are all signs of this disorder in women.

There are a number of factors that cause the body to generate excessive amounts of testosterone. These include androgen resistance, congenital adrenal hyperplasia, and ovarian cancer.

The use of anabolic steroids (manufactured androgenic hormones) stops the pituitary gland from secreting luteinizing hormone and follicle-stimulating hormone, which reduces the amount of testosterone and sperm contained in the testes. Prolonged use of anabolic steroids in men causes infertility, reduced sex drive, testicular shrinkage, and breast growth. Long-term attempts to detoxify anabolic steroids may cause liver damage. Changes in behaviour (such as irritability) can also be observed. Women who use anabolic steroids on a regular basis can experience undesirable side effects due to a high testosterone concentration.

What Happens if the Testosterone Levels are Too Low?

Male characteristics will not fully develop if testosterone deficiency occurs during fetal development. If a boy's development is slowed due to testosterone deficiency during puberty, he can not experience a growth spurt. Pubic hair production, penis and testicular growth, and voice deepening can all be slowed in the infant. Boys with low testosterone levels may have less strength and stamina during puberty, and their arms and legs may begin to develop out of proportion with the rest of their body.

Low testosterone levels in adult men can cause muscle loss, hair loss, and a wrinkled, parchment-like appearance to the skin. Men's testosterone levels gradually decrease as they get older. This is often referred to as male menopause in the media (andropause).

Low testosterone levels can lead to mood swings, increased body fat, muscle loss, insufficient erections and poor sexual performance, osteoporosis, attention problems, memory loss, and sleep problems. According to current studies, this effect affects only a small percentage of elderly men (about 2%).

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