The Pancreas

The Pancreas

Functions of the Pancreas 1. Exocrine Gland – Digestive System Pancreatic juices released into small intestine for chemical digestion (catabolism). Amylase (pancreatic) - enzyme that digests starch. Lipase - enzyme that digests lipids. Protease - enzyme that digests proteins.

Also in pancreatic juices: Sodium Bicarbonate - neutralizes HCl. Additional Digestive Enzymes Trypsinogen trypsin digests protein (zymogens) Ribonuclease digests RNA. Deoxyribonuclease digests DNA.

-cells site of insulin synthesis. 2. Endocrine Gland – Regulates Metabolism The islets of Langerhans (Pancreatic islets) are clusters of endocrine cells in the pancreas. -cells site of insulin synthesis. -cells site of glucagon synthesis. *Ghrelin – also from pancreas (and fundus of stomach), triggers hunger. delta-cells site of somatostatin synthesis.

The Glycemic Index (GI)

Insulin and Glucagon Insulin: peptide hormone made by  cells If blood glucose rises (e.g. after a meal) insulin is released. Insulin causes cells in body to take up glucose (e.g. ↓ blood glucose). Also causes liver to synthesize glycogen and other anabolic activities.

Glucagon: peptide hormone made by  cells If blood glucose falls (e.g. in between meals) glucagon is released. Causes liver to hydrolyze glycogen into glucose (e.g. ↑ blood glucose) Also causes fats and proteins to be converted into glucose (called gluconeogenisis) and other catabolic activities.

When blood Glucose is high Insulin is released to make blood Glucose lower (normal) Cells in your body up-take the glucose

When blood Glucose is low Glucagon is released to make blood Glucose higher (normal) Liver is key site: Hepatocytes liberate Glucose stores (glycogen) and use fats & proteins to make more glucose * *Glycogenolysis

Diabetes Mellitus Type I – “Juvenile Onset” (IDDM) Type II – “Adult Onset” (NIDDM)

Neurons can only use glucose! and don’t require insulin (use Glut-2-trans). Low blood glucose, e.g., hypoglycemia, can impair CNS resulting in dizziness, speech problems and loss of consciousness. Unconsciousness => “hypoglycemic coma" often resulting from "insulin shock”.

Insulin Levels

The Glycemic Index (GI)

Comparison of Molecules (120 Kcal each) Glucose Sucrose Ethanol 2 slices of bread. 1 glass of orange juice. 1 shot of bourbon.

Glucose Sucrose Ethanol ↑ Aldehydes ↑ Aldehydes 2 slices of bread 1 glass of orange juice 1 shot of bourbon 60 kcal glucose + 60 kcal fructose Starch => glucose CNS Depressant ~96 kcal used by all cells in body ~48 kcal used by all cells in body ~24 kcal used by all cells in body ~24 kcal hits Liver for Metabolism ~72 kcal hits Liver for Metabolism ~96 kcal hits Liver for Metabolism Glucose-6-℗ Glucose-6-℗ ↑ Aldehydes ↑ Acetate ↑ Citrate ↑ VLDL ↑ Aldehydes ↑ Uric acid ↑ VLDL + ↓NO = ↑BP Makes Glycogen ~0.5 kcal used for de novo Lipogenesis ↑ de novo Lipogenesis ↑ de novo Lipogenesis ↑ Insulin Dislipidemia Inhibits Ghrelin No effect on Ghrelin ↑Insulin resistance

Metabolic Syndrome Numerous metabolic risk factors in one individual, including: High Blood Pressure Abdominal Fat High blood Triglyceride levels High Uric Acid levels Insulin resistance State of chronic Inflammation Risks - cardiovascular disease and Type II diabetes mellitus. Est. over 50 million Americans have this condition. Hypothesized link to over consumption of high-fructose corn syrup (HFCS) and metabolic syndrome.