1.DR. LAXMIKANTA SAY

2. INTRODUCTION Galen- Latin pituita meaning mucus- pituitary secreted mucus or phlegm into nasal cavity Hypophysis outgrowth Pituitary -Hypothalamus single functional unit 3. PARTS 4. DEVELOPMENT 5. HISTOLOGY AdenohypophysisChromophilicAcidophilic Somatotropes-50% Lactotropes-10-30%ChromophobicBasophilic Corticotropes-10% Thyrotropes-5% Gonadotropes-20% 6. BLOOD SUPPLY 7. HORMONE OF ADENOHYPOPHYSIS 8. HORMONES OF NEUROHYPOPHYSIS 9. GROWTH HORMONE 10. GENERAL CHARACTERISTICS 1. Somatotrophin or Somatotrophic hormone 2. Synthesized by acidophils of anteriorpituitary & stored in pituitary gland. 3. Represents approx. 4 10% wet weight of pituitary (equivalent 5 15 mg of HGH) 4. Daily GH synthesis 0.2 1 mg/day in adults, biological half life 6 20 minutes. 5. A single unbranched polypeptide chain , 191 aminoacids with molecular wt. 21,500. 6.Long arm- chromosome 17, GH-hCS cluster containing five genes. 11. Cont.7. Species specific 8. Structural resemblance to prolactin& human chorionic somatomammotrophin (HCS) 9. Secreted episodically in periods of 20 30 min. with diurnal flucations. Nocturnal peak at deep sleep. 10. Plasma GH conc. child is 2 -4 ng/ml, adults 5 8 ng/ml 11. Mode of action ; cAMP mediated hormone activity 12. Factors affecting GH secretion Stimulator 1. Substrate deficiency - Hypoglycemia, Exercise, Fasting 2. GHRELIN 3. Oestrogen , Androgen , and decrease in FFA conc. 4. Increase in circulating amino acids - after protein meal, I.V. infusion of Arginine5. Glucagon 6. Emotional & stressful stimuli - Psychological stress, fear, trauma, Surgical operations - Pyrogens , Exposure to cold7. Deprived of REM sleep 8. Increase in brain Dopamine and Norepinephrine, 9. Apomorphine and Bromocriptin 13. Inhibitors 1. Release of GHIH (Somatostatin), Obesity 2. GH 3. Glucocorticoids ( cortisol) 4. REM Sleep 5. Glucose 6. FFA 7. Late Pregnancy (Increased Medroxyprogestron) 8. Old Age 14. Physiological actions of GH 1. Promotes Growth of Body Tissues2. Metabolic Effects - Protein & Mineral, - Insulin, -Carbohydrate & Fat4. Electrolyte metabolism 5. On Thymus 6. Lactation 15. Growth of Body Tissues Growth Factors - Somatomedins (A & B), - Thyroid , - Insulin (IGF- I & II) - Nerve growth factor, - Epidermal growth factor, - Ovarian growth factor, - Fibroblast growth factor, - Thymosin, - Multiplication stimulating activity, - Platelet derived growth factor (PDGF), - Relaxin, 16. Somatomedin Family of polypeptide, primary structuresimilar to Insulin Synthesized - Liver (main),Kidneys,Muscles Secretion : Independent of GH before birth, stimulated by GH after birth; peak at puberty (13 17 yrs of age) & decreased in old age. Plasma Level : 10 700 ng/ml Receptor : Similar to Insulin, Present on chondrocytes, adipocytes and muscles 17. Cont. Types : Four (A, C, IGF I & II) Major Actions : - Stimulates proliferation of chondrocytes, - Appearance of osteoblasts - Incorporation of sulphates into cartilage, - Stimulation of DNA & RNA synthesis, - Collagen formation in cartilage.Insulin Like effects on tissues - Lipolysis, glucose oxidation in fat, glucose, aminoacid transport by muscleActivity reduced by glucocorticoids & protein deficiency 18. Insulin like growth factors (IGF) IGF- IVsIGF - IIOther NameSomatomedin CMultiplication Stimulating Activity (MSA)Secretion-Independent before birth . -Stimulated after birth, -Peak at Puberty (13 17Yrs), -Low at Old age-Independent . -Constant throughout postnatal growth.Aminoacid7067SourceLiver & other tissueDiverse tissueRegulation-GH after birth, -Nutritional statusUnknownPlasma level10-700ng/ml300-800 ng/mlMajor Growth stimulating activity physiologic role Skeletal & cartilage growthFetal growth 19. Metabolic Effects 20. Protein Metabolism 1. Enhance amino acid transport through cellmembrane & promoting protein synthesis. 2. Enhance RNA translation to promoteprotein synthesis by ribosomes. 3. Increasing transcription of DNA to formRNA. 4. Decreasing catabolism of proteins & aminoacids. 21. Mineral Metabolism 1.Ca 2+ absorption2.Na+ , K +, Ca 2+ & Phosphorous excretion 22. Carbohydrate Metabolism 1.Glucose uptake by skeletal muscle 2. Promotes gluconeogenesis in liver 3. Insulin secretion 4. Opposes action of insulin & causes insulin resistance 5. Blood glucose level 6.Diabetogenic 23. Fat Metabolism 1. Catabolic effect mobilization of fats from adipose tissues - circulating FFA - gluconeogenesis - conversion of fatty acids to acetyl Co-A , used as a source of energy during hypoglycemia, fasting & stressful stimuli.2. Ketogenic breakdown or oxidation of fatty acids to ketone bodies, acetoacetic acid & hydoxybutyric acids. 24. Actions on Kidneys & Thymus Kidney Following removal of anterior pituitary- Kidney size decreases - GFR decreases - Renal blood flow decreases -Tubular secretion of PAH decreasesThymus - GH increases growth of thymus gland. 25. REGULATION OF SECRETIONS 26. Growth Periods 27. APPLIED ASPECTSGH DeficiencyExcess Secretion 28. DwarfismGrowth RetardationAfrican PygmiesGH Deficiency Laron - DwarfPituitary - DwarfHypothyroid Dwarf 29. Pituitary - Dwarf GH deficiency secondary to decreaseGHRH Characteristics features : 1. Plumpness (fatness) 2. Immature facies 3. Small genitalia 4. Delicate extremities, body proportion according to chronological age 5. Delayed skeletal & dental development 6. Low circulating hormone level 30. Hypothyroid - Dwarf 1. Gross retardation mental & physical 2. Body proportion infantile 3. Bone age retarded, more than height 4. Hypothyroid features 5. Early onset, more severe delay in growth & skeletal maturation. 31. Achondroplasia Autosomal Dominant disease Faulty endochondral ossification fibroblast growth factor 3 deficiency Features :1. Mentally sound 2. Abnormal body proportions - Large head, short limbs, normal trunk 3. Long bones thickened & stout 32. Kasper Hauser Syndrome Psycho social Dwarfism Emotional deprivation Features ;1. Immature facial appearance , behaviour & intellect 2. Bone age retarded in proportions to reduced height 3. Abdomen protuberant 4. Response to GH & ACTH deficient 33. Excess Secretion of GHGigantismAcromegaly 34. Gigantism 1. GH during Adolescent (before epiphysisclosure) 2. Excessive growth of long bone Clinical Characteristics : 1. Tall stature 2. Bilateral gynaecomastia 3. Large hands & feet 4. Coarse facial features 5. Loss of libido / impotence 6. 10% develop DM 35. Acromegaly Acromegaly enlargement of peripheral region Acidophilic tumor of anterior pituitary GH adulthood (after epiphysial closure) 20 40% associated with hyper secretion of prolactin Characteristic features ; 1. Prognathism elongation & widening of Mandible 2. Prominent Brow enlarged frontal, mastoid, ethmoid, & maxillary sinuses 3. Acromegalic facies thick shin, coarse face, oedema 4.Kyphosis periosteal growth of vertebrae, leads to bowing of spine 5. Acral parts 6. Hypertrophy of soft tissues - cardiomegaly, hepatomegaly, renomegaly, splenomegaly 36. THANK YOU