12.3 Endocrine control of reproduction

The endocrine control of reproduction involves a complex interplay of hormones from the hypothalamus, pituitary, and gonads. These hormones regulate sexual development, gametogenesis, and reproductive behavior in both males and females.

The hypothalamic-pituitary-gonadal axis forms a feedback loop that maintains reproductive function. Gonadotropin-releasing hormone from the hypothalamus stimulates the release of FSH and LH, which then act on the gonads to produce sex hormones and gametes.

Hypothalamic-Pituitary Hormones

Hormones Regulating Gonadal Function

Top images from around the web for Hormones Regulating Gonadal Function

• 

  The Pituitary Gland and Hypothalamus | Anatomy and Physiology I View original

  Is this image relevant?

• 

  Regulation of Body Processes | Boundless Biology View original

  Is this image relevant?

• 

  Frontiers | A Comparative Update on the Neuroendocrine Regulation of Growth Hormone in Vertebrates View original

  Is this image relevant?

• 

  The Pituitary Gland and Hypothalamus | Anatomy and Physiology I View original

  Is this image relevant?

• 

  Regulation of Body Processes | Boundless Biology View original

  Is this image relevant?

1 of 3

Top images from around the web for Hormones Regulating Gonadal Function

• 

  The Pituitary Gland and Hypothalamus | Anatomy and Physiology I View original

  Is this image relevant?

• 

  Regulation of Body Processes | Boundless Biology View original

  Is this image relevant?

• 

  Frontiers | A Comparative Update on the Neuroendocrine Regulation of Growth Hormone in Vertebrates View original

  Is this image relevant?

• 

  The Pituitary Gland and Hypothalamus | Anatomy and Physiology I View original

  Is this image relevant?

• 

  Regulation of Body Processes | Boundless Biology View original

  Is this image relevant?

1 of 3

• Gonadotropin-releasing hormone (GnRH) secreted by the hypothalamus stimulates the anterior pituitary to release FSH and LH
• Follicle-stimulating hormone (FSH) promotes follicle development in the ovaries and spermatogenesis in the testes
• Luteinizing hormone (LH) triggers ovulation and stimulates the production of estrogen and progesterone in the ovaries, and testosterone in the testes
• Prolactin, produced by the anterior pituitary, stimulates milk production in the mammary glands and plays a role in the maintenance of the corpus luteum in the ovaries

Hormones Involved in Reproductive Behavior and Childbirth

• Oxytocin, released by the posterior pituitary, stimulates uterine contractions during labor and delivery (childbirth) and promotes milk letdown during breastfeeding
  • Also involved in bonding, sexual behavior, and stress reduction

Gonadal Hormones

Hormones Produced by the Testes

• Testosterone, the primary male sex hormone, is produced by the Leydig cells in the testes
  • Responsible for the development and maintenance of male secondary sexual characteristics (muscle mass, deep voice, facial hair)
  • Stimulates spermatogenesis and sex drive (libido)

Hormones Produced by the Ovaries

• Estrogen, the primary female sex hormone, is produced by the granulosa cells in the ovarian follicles
  • Promotes the development and maintenance of female secondary sexual characteristics (breast development, fat distribution, pubic hair)
  • Regulates the menstrual cycle and prepares the uterus for implantation
• Progesterone, produced by the corpus luteum in the ovaries after ovulation
  • Maintains the uterine lining (endometrium) to support pregnancy
  • Inhibits ovulation and prepares the mammary glands for milk production
• Inhibin, secreted by the granulosa cells in the ovaries and Sertoli cells in the testes
  • Provides negative feedback to the anterior pituitary, suppressing FSH secretion to regulate follicle development and spermatogenesis

Reproductive Axis

Hypothalamic-Pituitary-Gonadal Axis

• The hypothalamic-pituitary-gonadal (HPG) axis is a complex feedback loop that regulates reproductive function
  • Hypothalamus secretes GnRH, stimulating the anterior pituitary to release FSH and LH
  • FSH and LH act on the gonads (ovaries and testes) to stimulate the production of sex hormones (estrogen, progesterone, and testosterone) and gametogenesis (oogenesis and spermatogenesis)
  • Sex hormones provide negative feedback to the hypothalamus and anterior pituitary, regulating the secretion of GnRH, FSH, and LH
  • This feedback loop ensures proper regulation of the reproductive system and maintains homeostasis
• Disruptions in the HPG axis can lead to reproductive disorders, such as hypogonadism, infertility, and menstrual irregularities