Insulin presentation

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Insulin presentation

  1. 1.  Introduction History Structure of insulin Biosynthesis Transport and catabolism Degradation Release of insulin Effects of insulin Clinical coorelations
  2. 2. INTRODUCTIONInsulin > protein hormone > by islets of langerhans > pancreasAnabolic hormone > growth & development
  3. 3. HISTORY• Canadian scientist (1921) –Fredrick G. Banting –Charles H. Best• extracted insulin –from dog’s pancreas
  4. 4. STRUCTURE OF INSULIN• Insulin – Polypeptide hormone – 51 amino acids – Two chains • A chain 21 a.a. • B chain 30 a.a.• Held by interchange disulfide bridges
  5. 5. BIOSYNTHESIS OF INSULIN Synthesis of Preproinsulin. Conversion of preproinsulin to proinsulin. Conversion of proinsulin to insulin.
  6. 6. GENETICS OF INSULIN SYNTHESIS The proinsulin precursor of insulin is encoded by the INS gene
  7. 7. Preproinsulin M.W 11500 109 A.A
  8. 8. ProinsulinM.W 9000 86 A.A
  9. 9. Insulin (21+30 A.A)
  10. 10. Human proinsulin and its conversion to insulin.
  11. 11. CATABOLISM OF INSULIN Half life: 3-5 minutes Major organs of degradation > Liver. >Kidney. >Placenta. 50% of insulin removed in a single pass through liver. MECHANISM : Insulin specific protease. Glutathione insulin transhydrogenase (Insulinase
  12. 12. Regulation of Insulin Secretion
  13. 13. Correlation Between Plasma Glucose & Insulin Levels
  14. 14. BIOLOGICAL EFFECTS OF INSULIN
  15. 15. Effect on carbohydrate metabolism⇑ Glucose uptake– Skeletal muscles– Cardiac muscles– Adipose tissue– Mammary glands
  16. 16. Effect on carbohydrate metabolism (contd) In s u lin in d e p e n d e n t t is s u e s  B r a in  RB C  Te s t i s  K id n e y  R e t in a  In t e s t in a l m u c o s a l c e lls
  17. 17. INSULIN MEDIATED GLUCOSE UP TAKE
  18. 18. CARBOHYDRATE METABOLISM Metabolism Net Effect Effect on important enzymeGlycolysis Increased Glucokinase Phosphofructokinase Pyruvate kinaseGlycogenesis Increased Glycogen synthataseHMP shunt Increased Glucose 6-phosphate dehydrogenaseGluconeogenisis Decreased Pyruvate carboxylase Phosphoenol Pyruvate carboxylakinase Glucose 6-phosphataseGlycogenolysis Decreased Glycogen phosphorylase
  19. 19. Lipid Metabolism Metabolism Net effect Effect on important enzymesLipogenesis IncreasedDeNovo FA Synthesis Increased Acetyl CoA carboxylase Avalbility of NADPHAdipose tissue Increased Provide α-glycerol-3-PO4 Lipoprotein lipaseLipolysis Decreased Hormone sensitive lipaseKetogenesis Decreased HMG CoA synthetaseLipoprotein Increased Utilization of VLDL & LDL
  20. 20. Protein MetabolismMetabolism Net Effect Effect on important enzymesProtein Increased RNA polymerasesynthesis Amino acids up takeProtein Decreased Transaminasesdegradation Deaminases
  21. 21. CELL GROWTH & DEVELOPMENT• Promote cell growth and development• Mediated by• Epidermal growth factors.• Platelet derived growth factor.• Prostaglandings.
  22. 22. CLINICAL CORRELATIONS
  23. 23. Symptoms of Diabetes • Frequent urination • Thirst • Hunger • Weight loss (despite thirst, hunger) • Fatigue • Vision impairment
  24. 24. Continued…
  25. 25. Continued…
  26. 26. LEPRECHAUNISM
  27. 27. INSULINOMAHYPERINSULINISM
  28. 28. Islet cell tumors, producing such symptoms, are called insulinomas
  29. 29. Insulin shock High level of insulin.Fall in blood glucose level.CNS depression.50-70 mg/dl CNS excitability20-50 mg/dl CONVULSION& COMA< 20 mg/dl COMA
  30. 30. HYPOGLYCAEMIA IN FETUS OF DIABETIC MOTHER Maternal blood glucose level. Transfered through placenta. Fetal blood glucose level.o β-cells of fetus secrete insulin.o Saturation of placenta 30 mmol/Lo Hypoglycaemia
  31. 31. REFERENCES• Lectures on “Endocrinology” by C.J.Baired MD/PhD• www.dtu.ox.ac.uk/4-T• Lectures on “Signaling Through Insulin Receptors” by Oksana Matveinko• Wikipedia• Arthur C.Guyton, John E.Hall, “Textbook Of Medical Physiology” 11th edition Ch: 78 Page:961-970• Lectures By MA Hussain & ND Theise “ Stem-Cell Therapy For Diabetes Mellitus”
  32. 32. Contd.• Robert K.Murray, Daryl K.Granner, Victor W.Rodwell, “Harper’s Illustrated Biochemistry” 27TH edition Ch:41 Page: 457• John T.Hensen, Bruce M.Koeppen, “Netter’s Atlas Of Physiology” 5th edition Ch:8 Fig. 8.19,8.20• Robert B.Dunn “Kaplan Medical Physiology USMLE Step 1 Lecture Notes” Section:9 Ch: 5 Page: 407-413• Insulin by Dr. Dana Armstrong and Dr. Allen Bennett King
  33. 33. Acknowledgements• Almighty Allah for giving me audacity for my each step to its triumphant completion My Parents Head of Biochemistry Department Dr. Shafqat Nazir All teachers of biochemistry department My Friends Library staff Projectionist
  34. 34. 43

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