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FOOD. sugars. fats. proteins. simple sugars (glucose). fatty acids. amino acids. lipids. glycogen. proteins. glucose. glucose. muscle. liver. fat. glucose. glucose. glucose. Metabolism. Gall bladder. liver. Bile Duct. Pancreas. Pancreatic duct. duodenum.

william-kennedy
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Metabolism

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  1. FOOD sugars fats proteins simple sugars (glucose) fatty acids amino acids lipids glycogen proteins glucose glucose muscle liver fat glucose glucose glucose Metabolism

  2. Gall bladder liver Bile Duct Pancreas Pancreatic duct duodenum Mammalian Pancreas -Exocrine Pancreas: secretes digestive enzymes, alkaline pancreatic fluid -Endocrine Pancreas: secretes hormones that regulate carbohydrate, lipid, and protein metabolism

  3. Islets of Langerhans Exocrine cells    capillaries Endocrine Pancreas • Islets of Langerhans: 4 cell types •  cells: secrete glucagon •  cells: secrete insulin •  cells: secrete somatostatin • F cells: secrete pancreatic polypeptide

  4. Pancreatic Hormones • Insulin • Glucagon • Somatostatin

  5. INSULIN • Regulation of Secretion • Hyperglycemia stimulates release • Glucose sensors in  cells • Gastric Inhibitory Peptide • Released from cells of the small intestine • Potent stimulator of insulin secretion • Somatostatin: inhibits insulin release (paracrine) • Autonomic nervous system • Parasympathetic activation increases insulin release • Sympathetic activation blocks insulin release • Epinephrine (from adrenal) blocks insulin release

  6. INSULIN • Action at Target Tissues • Activation of insulin receptor: • Increases transport of glucose, amino acids, and fatty acids into cells Glucose transporter:

  7. INSULIN • Action at Target Tissues • Activation of insulin receptor: • Increases transport of glucose (glucose transporter), amino acids, and fatty acids into cells • Enhancement of anabolic pathways, decrease in catabolic pathways • Increases enzymes that activate: • Glycogen formation (liver) • Lipogenesis (fat) • Protein Synthesis (muscle)

  8. Pancreatic Hormones • Insulin • Hypoglycemic, glycogenic, lipogenic, anabolic • Glucagon • Somatostatin

  9. Glucagon • Hyperglycemic (increases plasma glucose) • (one of many in the body) • Actions at target cells • Liver • Promotes glycogenolysis • Promotes gluconeogenesis • Fat Tissue • Promotes lipolysis

  10. Pancreatic Hormones • Insulin • Hypoglycemic, glycogenic, lipogenic, anabolic • Glucagon • Hyperglycemic, lipolytic • Somatostatin • Paracrine agent • Believed to inhibit insulin and glucagon release • Inhibits digestion through several pathways

  11. Insulin: decreases blood glucose levels  Glucagon: increases blood glucose levels  Somatostatin: inhibits insulin and glucagon levels (paracrine) and digestive processes Glucose Regulation

  12. DIABETES MELLITUS • Type 1—juvenile onset—insulin dependent • IDDM • Underproduction of insulin • Type 2—adult onset—non-insulin dependent • NIDDM • Insulin receptor resistance • Post-receptor mechanism problem

  13. Type 1 DiabetesInsulin Dependent: IDDM • Likely results from autoimmune reaction • The body’s immune system attacks the  cells • Pancreatic  markedly reduced • Symptoms only appear after ~80% loss of cells • No insulin……physiological repercussions? • Treatment • Insulin injections or insulin pump • Recent methods

  14. Separate islets from exocrine pancreas Encapsulate islets (immune protection) Inside the patient Inject into liver portal vein Islet Transplantation http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/

  15. Type 2 Diabetes:Non-Insulin Dependent: NIDDM • Accounts for 90-95% of all Diabetes cases • Usually occurs in overweight individuals over 40 years of age • But ages are getting younger and younger • Associated with abdominal fat in women • Target cells become resistant to insulin • insulin receptor • Fewer receptors • Receptors have lower affinity • Receptor blocked (possibly by antibody) • Post-receptor mechanisms

  16. Diabetes Prevelence in US % Incidence of diagnosed diabetes 1980 1990 2000 2007

  17. 2004 % of adults >20 2007

  18. New Cases in <20 yrs old

  19. Type 2 Risks 2006 • 7th leading cause of death • With Type 2 diabetes • 2 to 4-fold increase in heart disease related death • 2-fold risk of death • Type 2 associated complications • 2-4 fold risk of stroke • 75% of adults with Type 2 have high blood pressure • leading cause of blindness in adults aged 20-74 • Leading cause of kidney failure

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