Pancreas Flashcards
What are the lobes of the pancreas?
- Right (duodenal and thinner)
- Left (stomach, thicker)
What was the first protein to be produced using recombinant biotechnology?
Insulin
What is the exocrine portion of the pancreas?
Acinar cells that make pancreatic digestive enzymes
What is the endocrine portion of the pancreas?
Islets of langerhans
Which cells produce insulin?
Beta cells
What cells produce glucagon?
Alpha cells
What cells produce somatostatin?
Delta cells
What do epsilon cells produce?
Ghrelin (GH releasing peptide)
What are PP cells?
Produce pancreatic polypeptide
What regulates the release of insulin?-
- Glucose levels
- GI hormones
- Sympathetic input(inhibit)
- Parasympathetic (increase)
- Afferent taste from CN VII, IX, X
What is the synthesis of insulin?
Done in beta cells and starts as preprohormones with and A, B , cand C chain. It is then made into a prohormones and cleaved by proprotein convertase to cleave off the C terminal
What is the acute release of insulin?
Exocytosis of preformed insulin granules
What is the chronic phase of secretion of insulin?
Involves protein synthesis and insulin synthesis
What is the transport of insulin?
Water soluble so it is in the plasma and has a short half life
What is the main metabolic function of insulin?
-Increase glucose uptake through GLUT 4-Increase glycogen, triglyceride, and protein
What type of glucose produces a larger insulin response?
Oral glucose via X nerve
What inhibits insulin?
Glucagon
Catecholamines
What is the DMN of the vagal system?
Parasympathetic regulation
What is the sulfonylurea receptor?
K channel that is stimulated to close by an increase in ATP which depolarizes the cell
What is the ATP dependent release of insulin?
Glucose enters the beta cells and closes sulfonylurea receptors and causes depolarization. This the triggers Cav channels to open and get vesicle fusion and exocytosis of insulin
What is the K independent release of Insulin?
Glucose enters and ATP and directly causes release of insulin through exocytosis
What is the incretin effect on insulin?
Hormones secreted from stomach effect insulin production
What increases the synthesis of glucagon?
- Catecholamines
- Glucocorticoids
- amino acids
What decreases glucagon synthesis?
- High plasma glucose (insulin)
- High plasma fatty acids
What family does glucagon belong to?
Secretin family
How is glucagon released?
G-protein coupled receptors
What is the effect of glucagon on beta cells?
Stimulatory effect on beta cells
What produces glucagon?
Alpha cells
The actions of glucagon uses what action?
cAMP
What does the parasympathetic NS do to glucagon and insulin?
- Increase glucagon (help redistribute energy stores)
- Increase insulin (Break down glucose to use)
What does the sympathetic NS do to glucagon and insulin?
- Increase glucagon (liberate energy store)
- Decrease insulin
During fast, what should the whole blood glucose be?
- 60-120mg/dl in dogs cats and horses
- Can be varied with age or species
What is the fasting urinary/ renal glucose threshold?
-180mg/dl dogs
-300mg/dl cats
Means that there is more glucose than the body can use so this is the level in the blood that you start to see glucose in the urine
What glycosylated plasma proteins can you use to measure glucose?
-Hemoglobin A1c
-Albumin
Last in the blood longer so you can get a picture of the long term status of glucose
What tests can you use to test islet cell function?
- Glucose tolerance
- 3 glucose readings before and after eating
- Insulin RIA
What is diabetes mellitus?
Absolute or relative deficiency in insulin
What are some causes of diabetes mellitus?
- Dogs
-Canine parvovirus
Acinar necrotizing pancreatitis
-Beta cell exhaustion secondary to insulin resistance - Cats
-Amyloid deposition
-Beta cell exhaustion (secondary to insulin resistance)
3 Drugs
What are the clinical types of DM?
- nonketotic
- ketoacidotic
- hyperosmolar syndrome
What are some signs of DM?
- PD
- PU
- Glucose in urine
- Cataracts
- Weight loss in obese patients and polyphagia
- Hepatomegaly
- Acetone breath
What are some diagnosis of DM?
- Persistent fasting hyperglycemia
- Chronic hyperglycemia: HbA1c is high, glycosylated albumin
What does insulin complex with?
zinc in the blood
What are the forms of insulin?
- Hexamers formed by zinc ions
- Dimers
- Monomers
Which form of insulin is biologically active?
monomeric form
What is the effect of zinc on insulin?
Slows the release
How can we modify insulin to be faster acting?
Prevent zinc-mediated dimer or hexamer complexes
How could you make intermediate acting insulin?
Amorphous crystals allow for a large surface area which makes it dissociate faster than crystalline which are very slow
