Test 2 Diabetes Pathophysiology part 2 Flashcards
Q: which is NOT released by the beta-cells of the pancreas?
a. C-peptide
b. Insulin
c. Glucagon
d. Amylin
c. Glucagon
Q: Someone who has good blood glucose control over years is less likely to develop:
a. Retinopathy
b. Peripheral vascular disease
c. Cerebrovascular disease
a. Retinopathy-microvascular (has to do with control of glucose)
Q: What hormone is responsible for increasing blood glucose through promotion of glycogenolysis and gluconeogenesis
a. Insulin
b. GLP-1
c. Amylin
d. Glucagon
d. Glucagon
Non-Pharmacologic Diabetes Treatments
- Non-pharmacological treatments (always recommend)
- Diet—Decrease glucose/insulin spikes
- Well balanced – keep glucose from spiking too much
- Not a lot of processed simple sugars
- Physical activity—Increase glucose utilization and uptake by GLUT4
- Profound effect – significantly increases the level of GLUT4 that is available on cells(transporters that help pull glucose in from circulation)
- Weight Loss – may help to control Type 2 DM
- Diet—Decrease glucose/insulin spikes
Pharmacological Diabetes Treatment
- Insulin
- Sulfonylureas
- Meglitinides
- Biguanides
- Thiazolidinediones
- a-Glucosidase inhibitors
- Incretin mimetics
- Amylin analog
- SGLT2 inhibitor
Normal vs Diabetic Patients
- Normal:
- You eat food, gut absorption of carbohydrates causes postprandial hyperglycemia.
- Gut releases GLP1 and GIP to pancreas (incretin effect)
- helps increase insulin and decreases glucagon
- causes hepatic cells decrease glucose production
- peripheral muscle increases glucose uptake
- adipose tissue increase fat production
- Gut releases GLP1 and GIP to pancreas (incretin effect)
- Diabetes:
- You eat food, gut absorption of carbohydrates causes postprandial hyperglycemia.
- Gut releases about 50% less GLP1 and GIP to pancreas which decreases the incretin effect
- less the help to pancreas to release insulin impairing insulin release
- since insulin release is impaired the glucagon is not as strongly inhibited
- hepatic cells don’t as strongly decrease glucose production
- peripheral muscle have less glucose uptake
- adipose tissue lipolyse fat increasing glucose
- Gut releases about 50% less GLP1 and GIP to pancreas which decreases the incretin effect
Insulin Mechanism
- Insulin
- Required for Type 1 DM
- Also can be given for Type 2 DM (especially later after they’ve had DM for a while)
- Goal of therapy
-
Mimic normal insulin secretion
- Basal (mimics the low pulses→supresses gluconeogenesis)
- Give long-acting to mimic basal
- Prandial/Bolus (mimics insulin after meals-acute response)
- Give short acting to mimic bolus
- Basal (mimics the low pulses→supresses gluconeogenesis)
-
Mimic normal insulin secretion
- Source—recombinant DNA
- human insulin→low allergenicity
- not proinsulin like natural so does NOT increase C-peptide
- Strength—usually 100 units/ml (U-100)
Insulin Preparations differ on:
- Onset (how quickly will insulin peak and drop glucose)
- Duration of action (how long will it be active?)
- Absorption (different absorption rates from injection site vary their onset and DOA)
- Route (SC, IV, intranasal)

Insulin by duration/onset
- Rapid acting (short onset, short duration)
- Glulisine
- Lispro
- Aspart
- Short acting (a bit longer onset and duration)
- Regular
- Intermediate acting (a bit more time til onset, intermediate duration)
- NPH
- Long/Ultra-long acting:
- Detemir
- Glargine
- Degludec
- Ryzodeg (70% degludec + 30% aspart)

Inhaled insulin
- Afrezza—rapid acting insulin (bolus), inhalation use
- Cough, dry mouth, hypoglycemia possible
“Artificial pancreas”
- Medtronic MiniMed670G
- approved September 28, 2016!!! Available in Spring 2017
- Closed loop pump system
- sensors and pumps working together
- has sensors that checks blood glucose every 5 min and adjusts insulin delivery.
- It delivers insulin when needed→high glucose and doesn’t if not no need→low glucose
- Delivers basal insulin only, user must program bolus (prandial) doses based on the carb intake of meal
Insulin Adverse Effects
- Insulin Adverse Effects
-
Hypoglycemia
- confusion, may lose their balance and fall – common in elderly
- due too taking too much insulin or not eating when expected
- Action is independent of glucose in the blood
-
Weight gain
- insulin promotes lipogenesis (fat production) and pulls excess blood glucose into the cells→stored as glycogen and fatty acids)
- Insulin allergy (much less common now-animal is no longer used)
-
Hypoglycemia
Sulfonylureas MOA
- Sulfonylureas
- MOA—increase insulin release from beta-cells in pancreas by closing KATP channels through the sulfonylurea receptor; insulin secretagogues
- Sulfonylureas block ATP-dependent K+ channel →results in insulin release
- Also decreases serum glucagon (an indirect effect mediated via insulin – do not directly affect alpha-cells)
- MOA—increase insulin release from beta-cells in pancreas by closing KATP channels through the sulfonylurea receptor; insulin secretagogues
- Insulin secretion is independent of glucose
- will cause insulin secretion regardless of glucose levels
Sulfonylureas Adverse Effects
- Insulin secretion is independent of glucose
- Risk of hypoglycemia—action is independent of glucose levels
- Similar effect to insulin injections
- Risk of hypoglycemia—action is independent of glucose levels
-
Weight gain
- 1-3 kg (2 – 7 lb – affects the patient’s ability to monitor and regulate their blood sugar)
-
CV mortality increase? (glyburide especially, not very common in others)
- Sulfonylurea receptor present in some amount in cardiac myocytes and vascular smooth muscle – blocking activity at theses sites increases the patient’s risk of CV mortality
Sulfonylurea classes
- First generation—Less potent, more SE – NOT RESPONSIBLE FOR THESE
- Tolbutamide
- Chlorpropamide
- Tolazamide
- Second generation—safer and more commonly used today
- Glyburide
- Most problematic 2nd gen
- Non-hypoglycemic metabolites
- though some metabolites have a mild hypoglycemic effect (although low potency)
- Flushing possible with alcohol use
- Glipizide – has a slightly shorter half-life
- Glimepiride
- Glyburide
- Glipizide and glimepiride have less complications than glyburide
Non-Sulfonylureas MOA
- Repaglinide
- Nateglinide
- (aka: Meglitinides or Glinides)
- Block ATP-sensitive potassium channels in beta cells to increase insulin release
- Also insulin secretagogues, although slightly different binding site from sulfonylureas (share 2 of 3 binding sites with sulfonylureas)
- (aka: Meglitinides or Glinides)
Repaglinide
- Repaglinide (non-sulfonylurea)
-
Hypoglycemia possible
- if meal smaller than expected or if insufficient carbs
- MOA is independent of blood glucose levels
- Weight gain – insulin secretagogues
- Glucuronidation required for metabolism
- Glucuronidation inhibitors will increase half-life significantly (gemfibrozil).
- Decrease repaglinide dose.
- Glucuronidation inhibitors will increase half-life significantly (gemfibrozil).
-
Hypoglycemia possible
Nateglinide
- Nateglinide (non-sulfonylurea)
- D-Phenylalanine derivative
- Risk of hypoglycemia and weight gain
Q: Would combining a meglitinide with a sulfonylurea improve therapy?
No.
Work on 2 out 3 of the same binding sites – work essentially through the same mechanism
Biguanide MOA
- Metformin
- Only available Biguanide in the US – Phenformin has been discontinued in the US
- MOA—not fully understood
- Seems to increase insulin sensitivity (hepatic & muscle)
- Increased sensitivity involves activation of AMP kinase (AMPK – part of 2nd messenger system) - SENSITIZER
- Decreases hepatic glucose formation (especially gluconeogenesis in the liver; also glycogenolysis)
- Stimulation of uptake of glucose and glycolysis in muscle (including increase GLUT4) – “exercise pill”
- Mechanism is not dependent on functioning beta-cells – sensitizing insulin-resistant patient to the effects of insulin
- Not 1st line in Type 1 DM
Biguanide Side Effects
- Metformin
- Hypoglycemia is uncommon
- “Euglycemic” agent – sensitizes the patient to insulin action, but does not cause hypoglycemia on its own
- Seriously impaired kidney function can lead to accumulation of metformin – issues regarding lactic acid
- Hypoglycemia is uncommon
- Metformin Adverse Effects
-
GI (upset, diarrhea, anorexia) – especially when starting treatment
- Lessen with time and if taken with food
-
No weight
- No significant increase or loss in body weight is seen with use
-
GI (upset, diarrhea, anorexia) – especially when starting treatment
Thiazolidinediones MOA
- Pioglitazone
- Rosiglitazone
- (aka: TZDs, Glitazones)
- MOA—Agonists at PPAR-y (peroxisome proliferator activator receptor-y) – may also have activity at PPAR-a
- Nuclear receptor (regulate gene transcription – increases and decreases)
- PPAR-y receptors mostly found in adipose (fat) cells, but also in muscle cells
- Increase differentiation of adipocytes (stem cells → adipocytes – increases fat cell production)
- Encourages redistribution of fat from central (visceral) to peripheral (mostly done subcutaneous) – not adding visceral fat to diabetic patient
- The more fat cells we have taking glucose out of circulation, the better off the patient will be
- Increases secretion of adiponectin (don’t need to know)
- MOA—Agonists at PPAR-y (peroxisome proliferator activator receptor-y) – may also have activity at PPAR-a
- Require insulin be present to work (they increase insulin mediated glucose uptake)
- give the body more cells to take more glucose out of circulation
- Can be your own or injected.
- Raise HDL levels a bit, and conflicting effects on LDL and TG
- PPAR-a non-specific effects
- Full activity could take 1-3 months to be seen
- influencing differentiation of cells - may take a while to see effects but may see weight gain before then.
Thiazolidinediones Adverse Events
- Pioglitazone
- Rosiglitazone
- Full activity could take 1-3 months to be seen – influencing differentiation of cells - may take a while to see effects but may see weight gain before then.
- Weight gain (peripheral & subcutaneous, not visceral) – not increasing fat around the organs
-
Cardiovascular concerns
- May cause or exacerbate CHF (plasma volume expansion), MI, stroke
- Both have a black box regarding CHF
- Increased bone fractures and decreased hematocrit
- promoting differentiation of stem cells into fat cells (may have been bone cells or blood cells)
- Shunting from osteogenesis and red blood cell production to adipocyte differentiation
a-Glucosidase Inhibitors MOA
- Acarbose
- Miglitol
- MOA—Inhibition of a-glucosidase (breaks complex carbs to simple carbs) in intestines
- Delay digestion and absorption of starches and disaccharides because they can’t get absorbed as complex carbs
- Result: carbohydrates that are not absorbed, but pass through GI
- MOA—Inhibition of a-glucosidase (breaks complex carbs to simple carbs) in intestines
a-Glucosidase adverse effects
- Acarbose
- Miglitol
- No weight gain
- No effect on plasma lipids
- No hypoglycemia – may occur if combined with insulin/insulin secretagogue
- Digestional (due to fermentation)—Flatulence, diarrhea, abdominal pain, bloating
- May be severe enough to inhibit use
- Digestional (due to fermentation)—Flatulence, diarrhea, abdominal pain, bloating
Incretin Facilitators MOA
- Incretin Facilitators – increase insulin secretion
- GLP1 Receptor Agonists (injectables)
- Giving a supra-physiological dose (well above what the body would have had – have more potent effect than DDP-4 inhibitor)
- DPP-4 Inhibitors – degrades GLP1→ increases overall incretin effect (oral)
- Stop degradation of Incretins→ stop degradation of what body has already made
- Much more subtle effect than GLP1 agonist
- GLP1 Receptor Agonists (injectables)

GLP-1 receptor agonists
- GLP-1 receptor agonists:
- Exenatide
- Liraglutide
- Albiglutide
- Dulaglutide
- Lixisenatide
- MOA:
- GLP-1 receptor activation increases cAMP levels, increasing insulin synthesis and release in a glucose-dependent manner
- Agonists at GLP-1 receptor—increase insulin synthesis and release in a glucose-dependent manner
- Glucose is low → less of an effect at causing hypoglycemia
- Increase cAMP, increase insulin synthesis and release (that is mostly dependent on increased glucose levels)
- Also slows gastric empty rate & decrease feeding (by increasing satiety – eat less and feel full)

GLP-1 Receptor Agonist Side Effects:
- Exenatide
- Liraglutide
- Albiglutide
- Dulaglutide
- Lixisenatide
-
Nausea & vomiting—dose dependent (due primarily to satiety)
- Really more of “fullness”
- Eat slowly and don’t overeat – until they know how their body will respond to the medication
-
Weight loss
- Caused by less eating, not increased metabolic rate (same fullness w/o same calories)
-
Pancreatitis risk may be increased
- can inflame pancreas (not fully understood) – alert MD of abdominal pain
-
Nausea & vomiting—dose dependent (due primarily to satiety)
Not much hypoglycemia risk
DPP-4 inhibitors MOA
- Alogliptin
- Sitagliptin
- Saxagliptin
- Linagliptin
- MOA:
-
Block degradation of GLP-1 and GIP by dipeptidyl peptidase 4 (DPP-4), thus increasing levels of GLP-1 and GIP
- In pancreatic b-cells, GLP-1 receptor activation increases insulin synthesis and release in a glucose-dependent manner
-
Block degradation of GLP-1 and GIP by dipeptidyl peptidase 4 (DPP-4), thus increasing levels of GLP-1 and GIP
- Given orally
- May or may not see weight loss (much less common)
- MOA:

DPP-4 Inhibitors Side Effects
- Alogliptin
- Sitagliptin
- Saxagliptin
- Linagliptin
- May or may not see weight loss (much less common)
- No satiety or gastric emptying effects (much more subtle effect)
- Only physiological levels of GLP-1 are reached
- May cause increased risk of pancreatitis

Amylin Analogs
- Pramlintide
- Injectable (s.c.)
- Not good at decreasing glucose levels-not drug expected in production
- Amylin is made by b-cells in pancreas
- Slows gastric emptying
- Decreases appetite (not enough to cause significant weight loss)
- Decreases glucagon release
Amylin Analog Side Effects
- Pramlintide
- Weight loss – due to increased satiety and slowed gastric emptying (not as much as w/ GLP1 agonist)
- Nausea, vomiting may occur – eat slowly and don’t overeat
Sodium-glucose cotransporter 2 (SGLT2) inhibitor MOA
- Canagliflozin
- Dapagliflozin
- Empaglifozin
- MOA: Inhibition of sodium-glucose cotransporter 2 in proximal renal tubule
- Bottom line: Less glucose reabsorption from urine (which means more glucose in urine) – calories are also gone
- Insulin independent mechanism
- Indicated for T2DM ONLY (may be useful in T1DM however watch for ketoacidosis )

Sodium-glucose cotransporter 2 (SGLT2) inhibitor side effects
- Canagliflozin
- Dapagliflozin
- Empaglifozin
- Low to no risk of hypoglycemia – taking excess glucose that is filtered and letting the body get rid of it
- Some weight loss may be experienced
-
Glucose in urine = greater risk of infections
- Urinary tract infections in men and women
- Yeast infections in women
-
Rare risk Euglycemic ketoacidosis
- MOA is not fully understood
- seen in T1DM who should not be taking it
- T2DM seen with infection or some other predisposing factors
- Less glucose→Less insulin→ less inhibition of gluconeogenesis →more gluconeogenesis → more ketone bodies→less inhibition of glucagon →ketoacidosis with no C-peptide.
- Treatment: Not affecting blood glucose (don’t rehydrate, give insulin to stop ketone production)
- Very rare, but if they get an infection, they should monitor ketone bodies in their urine
Q: Which is NOT an insulin secretagogue? Select all
Sulfonylurea
A-glucosidase inhibitor
GLP-1 receptor agonist
Biguanides
A-glucosidase inhibitor
and
Biguanides