1. ENDOCRINE PANCREAS

2. Anatomy Location Pancreatic Islets (of Langerhans) –Alpha cells –Beta cells –Delta cells –F-cells

3. Hormones

4. Insulin Chemistry –Protein/Peptide 51 amino acids 2-chains –  &  –2 disulfide bridges –Proinsulin 86 amino acid protein C peptide Peptidases

5. Insulin Action

6. Insulin Receptor Kinase Autophosphorylation Phosphorylation of proteins Translocation of GLUT-4 Down-regulation

7. Glucose Transporter Proteins GLUT-1 GLUT-2 GLUT-3 GLUT-4: INSULIN REGULATED GLUT-5

8. Basic effect of Insulin Promotes uptake of glucose from the blood Promotes storage of energy- producing nutrients

9. Effect of Insulin on the Liver Stimulates glycogenesis Stimulates protein synthesis Increased production of triglycerides, cholesterol, and VLDL Inhibits glycogenolysis Inhibits ketogenesis Inhibits gluconeogenesis

10. Effect of Insulin on Skeletal Muscle Promotes protein synthesis Stimulates glycogen synthesis

11. Effect of Insulin on Fat Cells Promotes triglyceride storage

12. Insulin Regulation Factors that stimulate insulin secretion –High serum glucose –High serum amino acids –Enteric hormones Factors that inhibit insulin secretion –Glucagon –Somatostatin –  -adrenergic stimulation

13. Insulin Control  -CELL PANCREATIC ISLET SERUM GLUCOSE LIVER & MUSCLE GLUCOSE UPTAKE GUT HORMONES SERUM AMINO ACIDS GLUCAGON SOMATOSTATIN  -ADRENERGIC INSULIN SERUM GLUCOSE

14. Glucagon Chemistry –29 amino acid peptide –Proglucagon Action –Antagonizes the action of insulin –Acts primarily on the liver –Stimulates glycogenolysis –Stimulates gluconeogenesis –Stimulates ketogenesis

15. Glucagon Regulation PANCREAS  -CELL BLOOD SUGAR LIVER & MUSCLE GLUCAGON GLUCOSE BLOOD SUGAR SOMATOSTATIN SYMPATHETIC INNERVATION PARASYMPATHETIC INNERVATION G-I HORMONES CORTISOL

16. Somatostatin Chemistry –14 amino acid peptide –Prosomatostatin –G-protein linked receptor –Produced and secreted by many tissues Action –Paracrine Factor –Inhibits insulin & glucagon secretion Regulation

17. Pancreatic Peptide Chemistry –36 amino acid peptide Action –unknown Regulation –Serum levels increase after a meal, but do not increase after glucose infusion –Vagotomy abolishes response to meal

18. Glucose Homeostasis NORMAL SERUM GLUCOSE 80-120 mg/dl SERUM GLUCOSE SERUM GLUCOSE ISLET  -CELLS LIVER & MUSCLE METABOLIC DEMANDS INSULIN GLUCOSE UPTAKE ISLET  -CELLS LIVER & MUSCLE GLUCAGON GLYCOGENOLYSIS GLUCONEOGENESIS HYPERGLYCEMIC HORMONES MEALS