testosterone

Examples of testosterone in the following topics:

• Hormonal Regulation of the Male Reproductive System

  • If the pituitary gland is removed, spermatogenesis can still be initiated by follicle-stimulating hormone (FSH) and testosterone.
  • The Leydig cells are also capable of producing estradiol in addition to their main product, testosterone.
  • In the testes, LH binds to receptors on Leydig cells, which stimulates the synthesis and secretion of testosterone.
  • Testosterone is made in the interstitial cells of the testes.
  • The sequestering of testosterone in the testes is initiated by FSH, and only testosterone is required to maintain spermatogenesis.

• Aging and the Endocrine System

  • Testosterone is a steroid hormone secreted by the Leydig cells.
  • Estradiol is the female equivalent of testosterone and is secreted from granulosa cells.
  • In vitro, cells treated with testosterone demonstrated a decrease in Ab release.
  • However, the effects of testosterone are not as potent as that of estrogen.
  • As a result, the effects of AD are diminished in the presence of both estrogen and testosterone.

• Male and Female Gonads

  • The ovaries also secrete testosterone, although at a much lower level than in males.
  • Progesterone and estrogen are secreted by granulosal cells, whereas testosterone is produced by thecal cells.
  • Luteinizing hormone results in testosterone release.
  • The presence of both testosterone and follicle-stimulating hormone is needed to support spermatogenesis.
  • Testosterone is secreted by Leydig cells, which are located between the seminiferous tubules.

• Puberty

  • For boys, an androgen called testosterone is the principal sex hormone.
  • While testosterone produces all boys' changes characterized as virilization, a substantial product of testosterone metabolism in males is estradiol.
  • The conversion of testosterone to estradiol depends on the amount of body fat and estradiol levels in boys are typically much lower than in girls.
  • LH stimulates the Leydig cells of the testes to make testosterone and blood levels begin to rise.
  • Much of the testosterone moves into nearby cells called granulosa cells.

• Male Hormones

  • The onset of puberty is controlled by two major hormones: FSH initiates spermatogenesis and LH signals the release of testosterone.
  • LH also enters the testes, stimulating the interstitial cells, called Leydig cells, to make and release testosterone into the testes and the blood.
  • Testosterone, the hormone responsible for the secondary sexual characteristics that develop in the male during adolescence, stimulates spermatogenesis, or the process of sperm production in the testes.
  • A negative feedback system occurs in the male with rising levels of testosterone acting on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH .
  • In turn, the testes production of testosterone and the hormone inhibin inhibit the release of GnRH, FSH, and LH in a negative feedback loop.

• Adrenal Cortex

  • Zona reticularis, is the inner most cortical layer; the zona reticularis produces androgens, mainly dehydroepiandrosterone (DHEA) DHEA sulfate (DHEA-S), and androstenedione (the precursor to testosterone) in humans.
  • Testosterone : a hormone with a wide variety of effects, ranging from enhancing muscle mass and stimulation of cell growth to the development of the secondary sex characteristics.
  • Dihydrotestosterone (DHT): a metabolite of testosterone, and a more potent androgen than testosterone in that it binds more strongly to androgen receptors.
  • While androstenediones are converted metabolically to testosterone and other androgens, they are also the parent structure of estrone.

• Testes

  • Thee testes produce sperm (spermatogenesis) and androgens, primarily testosterone.
  • Luteinizing hormone results in testosterone release.
  • The presence of both testosterone and follicle-stimulating hormone (FSH) is needed to support spermatogenesis.
  • Leydig cells located between seminiferous tubules produce and secrete testosterone and other androgens important for sexual development and puberty, including secondary sexual characteristics such as facial hair and sexual behavior.
  • In addition, testosterone controls testicular volume.

• Biological Influences on Sexual Motivation

  • Biologically, sexual motivation is influenced by hormones such as testosterone, estrogen, progesterone, oxytocin, and vasopressin.
  • In males, testosterone appears to be a major contributing factor to sexual motivation.
  • Interestingly, testosterone levels in males have been shown to vary according to the ovulating state of females.
  • Males who were exposed to scents of ovulating women recorded a higher testosterone level than males who were exposed to scents of nonovulating women.
  • Research suggests that testosterone, oxytocin, and vasopressin are also implicated in female sexual motivation in similar ways that they are for males, but more research is needed to understand these relationships.

• Muscular Atrophy and Hypertrophy

  • As testosterone is one of the body's major growth hormones, on average, men find hypertrophy much easier to achieve than women.
  • Taking additional testosterone, as in anabolic steroids, will increase results.
  • In addition, testosterone is also a medically regulated substance in most countries, making it illegal to possess it without a medical prescription.

• Administering Hormones

  • The main types of hormones involved are oestrogens, progesterone or progestins, and sometimes testosterone.
  • Hormone replacement therapy for transgender, gender variant, and transsexual people introduces hormones associated with the gender that the patient identifies with (notably testosterone for trans men and estrogen for trans women).