testosterone

Examples of testosterone in the following topics:

• 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.

• Male Reproductive Anatomy

  • The reproductive tissues of male and female humans develop similarly in utero until a low level of the hormone testosterone is released from male gonads.
  • Testosterone causes the undeveloped tissues to differentiate into male sexual organs.
  • The testes, a pair of male reproductive organs, produce sperm and male sex hormones, including the steroid testosterone.
  • Other cells mixed in the wall of the tubules are the interstitial cells of Leydig; these cells produce high levels of testosterone once the male reaches adolescence.

• Lipid-Derived, Amino Acid-Derived, and Peptide Hormones

  • Examples of steroid hormones include estradiol, which is an estrogen, or female sex hormone, and testosterone, which is an androgen, or male sex hormone.
  • The structures shown here represent (a) cholesterol, plus the steroid hormones (b) testosterone and (c) estradiol.

• Pineal Gland and Gonads

  • Testosterone, the most prominent androgen in males, stimulates the development and functioning of the primary sex organs .
  • The testes produce androgens, such as testosterone, which regulate primary sex organ development and function, as well as the development of secondary sex characteristics and the production of sperm cells.

• Steroids

  • Cholesterol is also a precursor to many important steroid hormones like estrogen, testosterone, and progesterone, which are secreted by the gonads and endocrine glands.

• Termination of the Signal Cascade

  • One reason that hydrophobic hormones like estrogen and testosterone trigger long-lasting events is because they bind carrier proteins.

• Hormonal Regulation of the Reproductive System

  • The most widely-known androgen in males is testosterone, which promotes the production of sperm and masculine characteristics.
  • The adrenal cortex also produces small amounts of testosterone precursor, although the role of this additional hormone production is not fully understood.

• Signaling Molecules

  • Steroid hormones include the female sex hormone, estradiol, which is a type of estrogen; the male sex hormone, testosterone; and cholesterol, which is an important structural component of biological membranes and a precursor of steriod hormones .

• Types and Functions of Proteins

  • Some types of hormones, such as estrogen and testosterone, are lipid steroids, not proteins.

• Hydrocarbons

  • The benzene ring is present in many biological molecules including some amino acids and most steroids, which includes cholesterol and the hormones estrogen and testosterone.