Pancreatic Hormones (Insulin, Glucagon, Somatostatin)

Описание: The endocrine pancreas hormones such as Insulin, Glucagon, and somatostain physiology and pathophysiology explained for USMLE Step 1. is made up of 3 types of cells. Alpha cells secrete glucagon, Beta cells secrete insulin and Delta cells secrete somatostatin.

INSULIN
Generally speaking insulin is designed for energy abundance. So your body prefers to use glucose rather than fats for energy. The body will use CH instead of fat and glycogen. And use Amino Acids for protein synthesis.

GLUCOSE
Muscle will have increase uptake to make glycogen in the muscle. In the liver it will be used for uptake to use for glycogen and fat. Brain will only use glucose and this is independent of insulin.

FAT
Increase fat storage. Increase citrate and isocitrate. Increase AcetylCoA Carboxylase. This increase malonyl CoA which will increase Fat synthesis. This will increase Lipoprotein lilpase and decrease lipase. In Deficiency you prefer fats so you increase lipoprotein lipase which increase Free Fatty Acids. This will become phospholipids and cholesterol leading to heart disease. When there is Free Fatty Acids without insulin this will increase Ketone bodies (Acetoacetic Acid and B-hydroxyacetate).

PROTEIN
Increase synthesis and storage of protein. Increase AA and Increase Protein synthesis. In deficiency there is increase serum AA and increase urea in urine. It also increase effect on Growth Hormone.

MECHANISM OF ACTION of BETA Cell
When Glucose comes in this increases ATP and blocks Potassium channel. This depolarizes and causes opening of Calcium channel.

Regulated by glucose, Amino Acids, and GIT hormones.

GLUCAGON
This hormone is expressed when glucose is low. Therefore it will increase gluconeogenesis by converting Amino acids into glucose and converted fats into glucose. Increase cAMP which will increase Phorphokinase which will increase phorphorylase and increase glucose phosphate. Only small amount of glucose is necessary to have greater effects because of amplification. At really high concentrations it can increase heart contraction, increase blood flow to organs, increase bile secretion an block gastric acid.

SOMATOSTATIN
REgulated by high glucose, Amino Acids, Fatty Acids and GIT hormones.
Effects of somatostatin - decrease insulin and glucagon. Decreases motility of duodenum, stomach and gallbladder. Decreases secretion and absorption in GIT.