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Growth hormone
- 1. 1 Surah: 33 Al Ahzab Aya: 21 Growth Hormone Prof. Dr. Rashid Mahmood (Courtesy: Prof. Dr. M. Yousaf)
- 2. Outline Introduction Growth functions Metabolic Effects Requirements for Growth Hormone to cause growth Variations & Control (Regulation) of Growth Hormone Secretion ABNORMALITIES OF GROWTH HORMONE SECRETION 2
- 3. Introduction to Growth Hormone •Other names: •Somatotropic Hormone or Somatotropin •Secreted by: •Acidophils of Anterior Pituitary Gland 3
- 4. 4 Functions of Growth Hormone 1. Growth functions 2. Metabolic Effects
- 6. Growth functions of Growth Hormone •Growth of all tissue capable of growing •Proliferation of cells • Increase size of the cells •Differentiation of the cells •Bone and cartilage growth
- 7. 7 Growth hormone affects growth
- 8. 8 Bone and cartilage growth • GH→ ↑deposition of proteins by chondrocytes and osteogenic cells • GH→ ↑reproduction of bone forming cells • GH→ ↑conversion of chondrocytic cells into osteogenic cells • GH → ↑deposition of chondroitin- SO4 and collagen • GH→ ↑deposition of cartilage and then calcification at the epiphyseal cartilage→ elongation of the bone
- 9. Bone and cartilage growth • Epiphyseal cartilage is used up and disappears then no more elongation of bone is possible • GH→ ↑osteoblastic activity→ ↑ bone deposition • Thickness of the bone continues to increase even after disappearance of epiphyseal cartilage 9
- 10. Assessment Q. 1 • What is the effect of Growth Hormone on Cartilages?
- 12. 12 Metabolic Functions(Effects ) of Growth Hormone •Effects on •Protein Metabolism •Fats Metabolism •Carbohydrates Metabolism
- 13. 13 Effects of Growth Hormone on Protein Metabolism •↑ of almost all facets of Amino Acids uptake and Protein Synthesis •↓ Catabolism of Protein and Amino Acids
- 14. Effects of Growth Hormone on Protein Metabolism ↑ Transport of Amino Acids through Cell Membrane ↑ RNA Translation to cause protein synthesis by Ribosomes ↑ RNA Translation to cause protein synthesis by Ribosomes
- 15. Effects of Growth Hormone on Fats Metabolism • ↑ Fats Utilization for energy Adipose tissue Acetyl-CoA ↑ Acetoacetic acid Ketosis ↑ FA ↑mobilization Energy
- 16. Effects of Growth Hormone on Carbohydrates Metabolism 1. ↑ glucose production 2. ↑ insulin secretion ↑ blood glucose level Insulin resistance GH is diabetogenic ↓uptake by tissues, like muscles & fats
- 17. Assessment Q. 2 • How does excess Growth Hormone cause Diabetes Mellitus?
- 18. Outline Requirements for Growth Hormone to cause growth 18
- 19. Requirements for Growth Hormone to cause growth (Subtopic of “GROWTH PHYSIOLOGY”) •Insulin •Somatomedins •Thyroid Hormone •Dietary factors: •Carbohydrates •Proteins •Androgens, Estrogens
- 20. 20 Insulin and growth Insulin (transport some of the Amino Acids across the Cell Membrane) Growth hormone
- 21. Somatomedins (IGF-I= Somatomedin C ) Growth Promoting Actions
- 22. 22 Somatomedins •Pygmies of Africa lack Somatomedin C •Levi-Lorain dwarfs also have the same problem •Somatomedin C may be produced by local tissues for local growth
- 23. GH deficiency with or without thyroid hormone
- 27. Assessment Q. 3 •Why Growth Hormone cannot cause proper growth if there is deficiency of Insulin?
- 28. Outline Variations & Control (Regulation) of Growth Hormone Secretion 28
- 29. Summary of Direct & Indirect functions of Growth Hormone
- 30. 30 Variations in the secretion of GH GH secretion varies throughout the day
- 31. Feedback Control of Growth Hormone It secretion is increased by 1. starvation, 2. protein deficiency, hypoglycemia, 3. low concentration of fatty acids, 4. exercise, 5. excitement, 6. trauma and 7. Ghrelin
- 32. Control (Regulation) of Growth Hormone Secretion
- 33. Outline ABNORMALITIES OF GROWTH HORMONE SECRETION 33
- 36. Centre: Gigantism •Right: dwarfism •Left: normal
- 37. Dwarfs
- 41. Gigantism A 12 years old giant boy with his mother
- 43. Acromegaly
- 44. Acromegaly
- 45. Acromegaly
- 46. Acromegaly
- 47. Acromegaly
- 48. Progressive Development of Acromegaly
- 49. Assessment Q. 4 •Name the diseases caused by growth hormone excess in adults, and children.
- 50. Take Home points (1/3) • Growth Hormone, also called Somatotropic Hormone or Somatotropin, is secreted by Acidophils of Anterior Pituitary Gland • It causes Growth of all tissues capable of growing, including bones and cartilages •It increases the protein content of the body • It causes hyperglycemia and its excess may lead to Diabetes Mellitus •It increases the utilization of fats for energy • Insulin is an essential requirement for growth hormone to exert its growth related functions
- 51. Take Home points (2/3) • Growth effects of growth hormone are caused by intermediate substances called Somatomedins (also called Insulin-like growth factors; IGFs) that are synthesized by liver • Most important Somatomedin is Somatomedin-C (IGF-I) •Growth hormone is secreted in Pulsatile pattern. Its secretion is highest during first two hours of deep sleep • It secretion is increased by starvation, protein deficiency, hypoglycemia, low concentration of fatty acids, exercise, excitement, trauma and Ghrelin
- 52. Take Home points (3/3) • Its secretion is controlled by releasing hormones produced by hypothalamus in a negative feedback control mechanism. GHRH (growth hormone-releasing hormone) increases its secretion, and growth hormone inhibitory hormone (also called Somatostatin) decreases its secretion • Panhypopituitarism causes multiple general deficiency effects in adults, while in children it may lead to Dwarfism. • Dwarfism may also be caused in cases where there is hereditary inability to form Somatomedin-C • Excessive secretion of growth hormone in adults causes Acromegaly, while in children it leads to Gigantism
- 53. The End Thank You Questions ? Comments drrashid62@gmail.com rashid.mahmood@rmi.edu.pk ppt also available at https://www.slideshare.net