Chapter 41: Pancreatic Hormones and Anti-diabetic Drugs Flashcards
What are the two main functions of the pancreas?
Endocrine Function- Islet of Langerhans
Exocrine Function - majority of the pancreas, produce digestive enzymes for proteins, lipids, and carbohydrates
What are the type of cells within the Islet of Langerhans?
Alpha cell- Glucagon, proglucagon
Beta cell- Insulin, C-peptide, proinsulin, amylin
Delta cell- Somatostatin (inhibitory peptide- insulin, glucagon)
G cell- Gastrin
F cell- Pancreatic polypeptide (PP)- GI motility
What are the Four Types of Diabetes Mellitus?
Type I - Insulin Dependent (IDDM), destruction of beta cells, no insulin, greater than 80% loss of beta cells
Type II - Non-insulin Dependent (NIDDM)
Type III - Other causes elevate blood glucose (pancreatitis, drug therapy)
Type IV- Gestational
What are the 3 main symptoms of diabetes?
Polyuria
Polydipsia (thirsty)
Polyphagia (hungry)
What is glycosylation?
What happens when glucose levels are too high?
Attaching a glucose molecule to another protein.
You will have nonenzymatic attachment of glucose molecules to proteins hence nonenzymatic glycosylation. This is mostly seen in HgB A1c. Normal level is 4-5%, Diabetics is 7-8%
What is the Polyol Pathway?
Glucose enter into certain cells in the body like the eye, nerve, and RBC will convert glucose into sorbitol and fructose.
Sorbitol and fructose can’t leave the cell and will attract water increasing intracellular osmotic pressure leading to cell injury.
What enzyme can be turned on by glycosylation?
Protein Kinase C, random activation of proteins
What are microvascular disease associated with chronic complication of DM?
Retinopathy (blindness)
Diabetic Nephropathy - kidney damage
What cells produce insulin?
What is measured to see how much endogenous insulin a patient is producing?
Beta cells produce pro forms of insulin, activated in the granules.
C-peptide
Describe the insulin receptor?
What are the effects of the receptor?
Tyrosine Kinase Receptor
Multiple effects:
Membrane Translocation of GLUT
Increase glycogen formation
Activation of multiple transcription factors
What is the term that describes something that causes the release of insulin?
Insulin Secretagogue
Glucose is the number 1 insulin secretagogue
Describe how insulin is released from the beta cells.
Essay Question
- The pancreas has GLUT-2 (low affinity for glucose)
- After a meal, there will be a high amount of glucose circulation that will enter GLUT-2.
- Glucose goes through metabolism in the pancreas and generates a lot more ATP
- ATP in the pancreatic beta cell closes K+ channel (Rectifier current), causing depolarization.
- Depolarization causes VG Ca2+ to open
- Ca2+ floods into the cell and causes exocytosis of insulin
What is the affinity for glucose for these GLUTs?
GLUT-1
GLUT-2
GLUT-4
GLUT-1- High affinity (brain, RBC)
GLUT-2- Low affinity (pancreas)
GLUT-4- Intermediate affinity (skeletal muscles)
What are the endocrine effects of insulin?
Inhibits glycogenlysis (decrease release of glucose)
Inhibits fatty acid release
Promotes glucose storage as glycogen
What are the 4 different types of insulin preparations?
- Rapid Acting - Lispro, aspart, glulisine
- Short Acting (Regular)- Novolin, Humulin
- Intermediate Acting- Neutral protamine Hagedorn (NPH)
- Long Acting- Glargine, detemir, degludec* (Basal)
What are the different types of Insulin Regimens?
Intensive
IDDM:Tight control
Basal + bolus (calculated)
Conventional
70:30 mix of regular/nph, okay control
Sliding scale regimen
Illness: Metabolic rate increases, need more glucose into the cell.
DKA/ HHS
Calculating Insulin Dose
Basal- 1 injection of long acting insulin in the AM
Bolus - Carb Coverage (1 unit of rapid acting insulin covers 12-15g of carbs)
Example: lunch you eat 60g of carbs
Inject 4 units of RA insulin (60/15 = 4 units)
What is the calculation for a correction of high glucose?
1 unit of RA insulin needed to drop 50 mg/dL
Example: Glucose spikes to 200 mg/dL
Inject 2 units of RA insulin (50 mg/Dl x 2 = 100 mg/dL drop)
What are the 8 oral antidiabetic agents (type II)?
- Biguanides- metformin
- Insulin Secretagogues- sulfonylureas
- Thiazolidinediones (TZDs)- decrease insulin resistance
- Alpha-glucosidase Inhibitors- Acarbose - used in pre-diabetics
- Bile Acid Sequestrant- BABR
- Amylin Analogs - Suppress Glucagon Release
- Incretin-base Therapies- GLP-1 agonist, DPP-4 antagonist
- SGLT2 Inhibitors - Gliflozins
What is first line treatment for NIDDM?
How does it work?
Biguanides (metformin, glucophage)
Reduce hepatic glucose production, less glucose removed from glycogen, less glucose going out into the blood stream
How do Insulin Secretagogues work?
What are the classes of Insulin Secretagogues?
What is the biggest difference between 1st and 2nd generation of Insulin Secretagogues?
Insulin Secretagogues bind to the K+ Channel and closes the channel causing depolarization which will release insulin.
Sulfonylureas- 1st gen, sulfa allergies
Meglitnide/Glipizide/Glyburide - 2nd gen, short half life
grams to milligram doses.
2nd gen is safer do to smaller dose.
What adverse effects was reported for Tolbutamide (Sulfonylureas)?
Adverse Cardiac Effects.
first generation sulfonylureas