L4.2.3: Testosterone Production

• Hypothalamus

  ○ Ensures that there is a proper communication between the nervous system and the endocrine system.

  ■ Communication through impulses

  ■ Communicates to the organs through the chemical messengers—hormones, through the help of the endocrine system.
• Hypothalamus

  ○ Regulation of the pleasure-centers of a body.

  ■ Site for hunger

  ■ Site for thirst

  ■ Site for sexual satisfaction/gratification
• Endocrine System

  ○ Coordinates with the reproductive system.

  ○ Pituitary Gland: the master gland of the endocrine system.

  ■ Has access to a target organ for them to produce their hormones.

  ■ Releases gonadotropins — FSH and LH: Male and female gonadotropins have different functions.
• Hormones

  • GnRH: gonadotropin-releasing hormone
  • FSH: Follicle-stimulating Hormone
  • LH: Luteinizing Hormone
  • Testosterone
• GnRH – gonadotropin-releasing hormone

  ○ Communicates from the hypothalamus to the pituitary gland (endocrine system).

  ○ Stimulates the function of the pituitary gland.
• FSH — Follicle-stimulating Hormone

  ○ Gonadotropin

  ○ Stimulates spermatogonia

  ○ Play an important role in the production of sperm through the wall of the seminiferous tubule.
• LH — Luteinizing Hormone

  ○ Gonadotropin

  ○ Plays an important role in the production of testosterone.
• Testosterone — a sex hormone

  ○ Primary and secondary sex characteristics

  ○ Final trigger for spermatogenesis

  ○ Enhance spermatogenesis

  ○ Trigger the interstitial cells. to release testosterone.
• Process of Testosterone Production

  [1] The hypothalamus releases gonadotropin-releasing hormone (GnRH)

  [2] The GnRH stimulates the anterior pituitary to release gonadotropins—FSH and LH.

  [3] FSH stimulates spermatogonia to produce sperm.

  [4] LH stimulates the interstitial cells to release testosterone, which serves as the final trigger for spermatogenesis. Testosterone then enhances spermatogenesis.

  [5] The rising level of testosterone exerts negative feedback control on the hypothalamus and pituitary.