Testosterone Male Development

During human development, many different hormones play critical roles to ensure that complex changes in throughout the body progress on the proper time course. For the changes that mark sexual maturation in males, no hormone is more essential than testosterone.

About Testosterone

Testosterone is a chemical that travels through the bloodstream. Consequently, testosterone comes in contact with many different cells of the body. Those cells that have the receptor for testosterone will bind to testosterone. The binding of testosterone to its receptor causes changes in gene activation inside that particular cell. Many different kinds of cells respond to testosterone, and the result of testosterone/receptor binding varies depending on the cell type and the amount of testosterone.

Like all hormones, testosterone is synthesized by glands and then secreted. In men, most testosterone is produced in the testes glands, although some is also made within the adrenal glands.

Testosterone belongs to a class of hormones called “androgens.” All androgens have roles in the development of masculine traits. Because testosterone is the most critical of the androgens, sometimes the terms androgen and testosterone are used interchangeably.

Testosterone and Male Development in Adolescence

Testosterone is produced in both boys and girls starting in infancy, but the levels are relatively low. In the adolescent male, testosterone levels throughout the body start to escalate. This escalation in testosterone occurs as the result of brain signals that induce the testes to produce more testosterone. This rise in testosterone is largely responsible for many of the physical and mental changes that take place during male puberty, including:

  • Hair growth on face and body
  • Height increase
  • Muscle development
  • Sexual awareness
  • Sperm production.

Male Development in Adolescence - Testosterone and Male Development

All of these changes take place as a result of activation (or deactivation) of certain genes within the target cells that come in contact with testosterone as it circulates through the bloodstream. In cells that make up hair follicles, for example, testosterone may induce the cell to grow hair.

Effects of Low Testosterone During Development

Much of what is known about how testosterone impacts sexual development in males has been learned through cases in which testosterone failed to perform its normal duties. Males who produce significantly lower than normal testosterone levels have a condition called testosterone deficiency, or “hypogonadism.” Testosterone deficiency can be caused by a genetic condition, or it may be the result of an injury or secondary medication condition that impacts testosterone production.

When testosterone levels are too low during development of the fetus, the sex organs often do not develop properly. This effect points to the importance of testosterone during these very early stages of human development. When low testosterone levels occur during adolescence, the affected male may not develop a normal sex drive or produce viable sperm. They may also fail to build up muscle mass or develop facial hair, and they may experience depression or other mood disorders. This wide range of symptoms indicates just how varied a role testosterone plays during this critical developmental period.


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