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Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
Anterior Pituitary
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Anterior Pituitary

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  • 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 Adenohypophysis Chromophilic Acidophilic Somatotropes-50% Lactotropes-10-30% Chromophobic Basophilic 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 anterior pituitary & 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 Arginine 5. Glucagon 6. Emotional & stressful stimuli - Psychological stress, fear, trauma, Surgical operations - Pyrogens , Exposure to cold 7. Deprived of “REM” sleep 8. Increase in brain Dopamine and Nor–epinephrine, 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 Tissues 2. Metabolic Effects - Protein & Mineral, - Insulin, -Carbohydrate & Fat 4. 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 structure similar 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 muscle Activity reduced by glucocorticoids & protein deficiency
  • 18. Insulin like growth factors (IGF) IGF- I Vs IGF - II Other Name Somatomedin C Multiplication Stimulating Activity (MSA) Secretion -Independent before birth . -Stimulated after birth, -Peak at Puberty (13 – 17Yrs), -Low at Old age -Independent . -Constant throughout postnatal growth. Aminoacid 70 67 Source Liver & other tissue Diverse tissue Regulation -GH after birth, -Nutritional status Unknown Plasma level 10-700ng/ml 300-800 ng/ml Major Growth stimulating activity physiologic role Skeletal & cartilage growth Fetal growth
  • 19. Metabolic Effects
  • 20. Protein Metabolism 1. Enhance amino acid transport through cell membrane & promoting protein synthesis. 2. Enhance RNA translation to promote protein synthesis by ribosomes. 3. Increasing transcription of DNA to form RNA. 4. Decreasing catabolism of proteins & amino acids.
  • 21. Mineral Metabolism 1. Ca 2+ absorption 2. 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 & βhydoxybutyric 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 decreases Thymus - GH increases growth of thymus gland.
  • 25. REGULATION OF SECRETIONS
  • 26. Growth Periods
  • 27. APPLIED ASPECTS GH Deficiency Excess Secretion
  • 28. Dwarfism Growth Retardation African Pygmies GH Deficiency Laron - Dwarf Pituitary - Dwarf Hypothyroid Dwarf
  • 29. Pituitary - Dwarf GH deficiency – secondary to decrease GHRH 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 GH Gigantism Acromegaly
  • 34. Gigantism 1. GH during Adolescent (before epiphysis closure) 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

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