Download MBBS Physiology Presentations 12 Pancreatic Hormones Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Physiology 12 Pancreatic Hormones PPT-Powerpoint Presentations and lecture notes

Endocrine secretions of

Pancreas

Endocrine secretions from islet of

Langerhans

Insulin- cells
Glucagon- cells
Somatostatin- cells
Pancreatic Polypeptide ? F cells
Insulin

First isolated by Banting and Best in 1922
Insulin is a polyopeptide containing 2 amino

acid chains linked by di-sulfide linkage

It is synthesized in RER as preproinsulin
It is cleaved into proinsulin

Effect of insulin on carbohydrate

metabolism

Promotes muscle glucose uptake and

metabolism

Storage of glycogen in muscles
Promotes liver uptake, storage and use of

glucose

- Inactivates liver phosphorylase
- Increases activity of glucokinase
- Increases activity of glycogen synthesis
Promotes conversion of excess glucose into

fatty acids and inhibits gluconeogenesis in liver
Effect of insulin on Fat metabolism

Promotes fat synthesis and storage
- Increases transport of glucose into

hepatocytes

- Pyruvate is converted to acetyl co-A
- Fatty acids synthesized are used to form

triglycerides

Insulin activates lipoprotein lipase in the

capillary walls

Insulin deficiency causes lipolysis of storage

fats and release of free fatty acids

Effect of insulin on Protein

metabolism

Promotes protein synthesis and storage
- Stimulates transport of amino acids into the

cells

- Increases translation of mRNA
- Increases rate of transcription
- Inhibits protein catabolism
- Depresses gluconeogenesis
Insulin and growth hormone interact

synergistically to promote growth
Glucagon

It is a large polypeptide secreted by -cells

of islet of landerhans

It is called as hyperglycemic hormone
It is glycogenolytic, gluconeogenic, lipolytic

and ketogenic

It acts via Gs to activate adenylyl cyclase

and increase intracellular cAMP

Glucagon

Glucagon does not cause glycogenolysis in

muscle

It increases gluconeogenesis in liver and

elevates metabolic rate

It increases ketone body formation
The calorigenic action of glucagon is not due

to hyperglycemia but due to hepatic

deamination of amino acids

Large doses have inotropic effect on heart
stimulated

inhibited

Insulin-glucagon molar ratios

Insulin is glycogenic, antigluconeogenetic,

antilipolytic and antiketotic

Glucagon is glycogenolytic,

gluconeogenetic, lipolytic and ketogenic
stimulated

inhibited

Hypoglycemic unawareness
Functional hypoglycemia
Persistent hyperinsulinemic hypoglycemia of

infancy

Macrosomia
Diabetes Mellitus Type 1 and Type 2