The Pancreas

The Pancreas

Functions of the Pancreas1. Exocrine Gland – Digestive System

Pancreatic juices released into small intestinefor chemical digestion (catabolism).

Lipase - enzyme that digests lipids.

Amylase (pancreatic) - enzyme that digests starch.

Protease - enzyme that digests proteins.

Additional Digestive Enzymes

Trypsinogen trypsin digests protein (zymogens)

Ribonuclease digests RNA.

Deoxyribonuclease digests DNA.

Sodium Bicarbonate - neutralizes HCl.

Also in pancreatic juices:

2. Endocrine Gland – Regulates Metabolism

The islets of Langerhans (Pancreatic islets)are clusters of endocrine cells in the pancreas.

-cells site of glucagon synthesis.

-cells site of insulin 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 highInsulin is released to makeblood Glucose lower (normal)

Cells in your bodyup-take the glucose

When blood Glucose is lowGlucagon is released to makeblood 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)

Sucrose EthanolGlucose

2 slices of bread. 1 glass of orange juice. 1 shot of bourbon.

Sucrose EthanolGlucose2 slices of bread 1 glass of orange juice 1 shot of bourbon

~96 kcal used by all cells in body

~24 kcal hits Liver for Metabolism

Dislipidemia

~24 kcal used by all cells in body

~96 kcal hits Liver for Metabolism

~48 kcal used by all cells in body

~72 kcal hits Liver for Metabolism

↑ Aldehydes ↑ Uric acid

↑ VLDL + ↓NO = ↑BP

↑ Aldehydes ↑ Acetate ↑ Citrate↑ VLDL

Makes Glycogen

↑ Insulin

60 kcal glucose + 60 kcal fructose

Starch => glucose

Glucose-6-℗ Glucose-6-℗

~0.5 kcal used for de novo Lipogenesis

No effect on Ghrelin ↑Insulin resistance

CNS Depressant

Inhibits Ghrelin

↑ de novo Lipogenesis ↑ de novo Lipogenesis

Metabolic SyndromeNumerous metabolic risk factors in one individual, including:

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.

High Blood Pressure

Abdominal Fat

High blood Triglyceride levels

High Uric Acid levels

Insulin resistance

State of chronic Inflammation