Session 4 Hormonal control, puberty, menopause

• Female (produces few gametes intermittently) - Intermittent fertility.

  Males produce large numbers of gametes continuously.
• Anterior pituitary - Arises from Rathke’s Pouch.
• Posterior Pituitary - Secretes ADH and Oxytocin.
• Testosterone reduces LH & FSH secretion.
• Oestrogen at moderate titres reduces LH & FSH secretion.
• Oestrogen alone at high titres increases LH & FSH secretion
• Inhibin from gonad inhibits FSH secretion selectively.
• Activins have a variety of local actions but also feedback to the pituitary to activate FSH secretion.
• Leptin able to stimulate GnRH production via kisspeptin.
• Testosterone is converted by aromatase (FSH) to oestrogen in females
• Signs of puberty before age of 8 in girls and age of 9 in boys - precocious puberty
• Precocious puberty can be classified according to Gonadotrophin:

  • Gonadotrophin dependent ("driven"). CNS/hypothalamus/pituitary disorders.
  • Gonadotrophin independent. Oestrogen/androgen driven. Isosexual. Heterosexual. Virilisation. Feminisation
• Prader Orchidometer - Medical device used to measure size of testicles
• Puberty - Tanner staging
• Tanner Staging?

  • Stage 1: Hormone release begins but no physical changes.
  • Stage 2: First physical changes noticeable - Girls: breast bud. Boys: testes and scrotum enlargement.
  • Stage 3: Growth spurt, physical changes progress - Girls: fat deposits on hips in girls, Boys: voice cracking and nocturnal ejaculation.
  • Stage 4: Key functional events - Girls: menarche, Boys: spermatogenesis
  • Stage 5: Adult physical appearance and function- Girls: regular periods and ovulation, Boys: facial hair and musculature