GnRH Triggers the Hormonal Cascade of Puberty
- Puberty begins when the hypothalamus increases the secretion of gonadotropin-releasing hormone (GnRH).
- This peptide hormone is released in pulses, which is critical for its effectiveness.
- GnRH acts on the pituitary gland, triggering the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
- Together, these hormones stimulate the gonads to produce sex hormones, which drive the physical and physiological changes of puberty.
Definition
Gonadotropin-Releasing Hormone (GnRH)
GnRH is a peptide hormone secreted by the hypothalamus in the brain. It regulates the reproductive system by stimulating the anterior pituitary gland to release two key hormones: luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
- GnRH is released in pulses, not continuously.
- This rhythmic release is essential for its effectiveness in stimulating LH and FSH production.
LH and FSH Drive Sex Hormone Production
- Luteinizing Hormone (LH):
- In males: LH stimulates the testes to produce testosterone, which drives changes like increased muscle mass and deepening of the voice.
- In females: LH triggers the ovaries to produce oestradiol and supports ovulation during the menstrual cycle.
- Follicle-Stimulating Hormone (FSH):
- In males: FSH promotes sperm production in the testes.
- In females: FSH supports the growth and maturation of ovarian follicles, which produce eggs.
Don’t confuse LH (primarily hormone production) with FSH (primarily gamete maturation).
Sex Hormones and Their Effects on Puberty
- Testosterone in males:
- Stimulates the growth of the penis and testes.
- Drives the development of secondary sexual characteristics like facial hair and a deeper voice.
