Pituitary gland

• Anterior pituitary has 3 parts:

  1. pars distalis
  2. pars tuberalis
  3. pars intermedia
• Anterior pituitary has 2 types of cells:

  1. chromophobe cell: do not possess granules and are poorly stain. form 50%. not secretory.
  2. chromophil cells
• Classification of chromophil cells:

  OBTO staining property:

  1. acidophilic
  2. basophilic


  OBTO secretory nature:

  1. Somatotrophs secrete growth hormone.
  2. Corticotrophs secrete adrenocorticotrophic
  3. Thyrotrophs secrete THS
  4. Gonadotrophs secrete FSH and LH
  5. Lactotrophs secrete prolactin
• Hormones secreted by anterior pituitary:

  1. GH or somatotrophic hormone
  2. TSH or thyrotropic hormone
  3. ACTH
  4. FSH and LH (ICSH in males)
  5. Prolactin
• Action of growth hormone:

  On protein metabolism:

  • Increasing amino acid transport through cell membrane
  • Increasing RNA translation
  • Increasing transcription of DNA to RNA
  • Decreasing catabolism of protein
  • Increasing anabolism of protein indirectly by increasing release of insulin
• Action of growth hormone:

  On fat metabolism:

  • increases mobilization of fats from adipose tissues.
• Action of growth hormone:

  On carbohydrate metabolism:

  1. Decrease in peripheral utilisation of glucose for production of energy
  2. Increase in deposition of glycogen in cells
  3. Decrease in uptake of glucose by cells
  4. Diabetogenic effect
• How GH increases bone growth

  1. Synthesis and deposition of proteins by chondrocytes and osteogenic cells

  2. Multiplication of chondrocytes and osteogenic cells by enhancing the intestinal calcium absorption

  3. Formation of new bones by converting chondrocytes into osteogenic cells

  4. Availability of calcium for mineralization of bone matrix
• Signs and symptoms of acromegaly:

  1. gorilla face
  2. Prognathism (protrusion of lower jaw)
  3. Enlargement of hands and feet
  4. kyphosis (extreme curvature of upper back)
  5. bull-dog scalp
  6. overgrowth of body hair
  7. enlargement of visceral organs
  8. hyperactivity of thyroid, parathyroid, adrenal
  9. hyperglycemia and glucosuria
  10. hypertension
  11. headache
  12. bitemporal hemianopia