Lecture 5: The Endocrine Pancreas Flashcards
D1 cells of the endocrine pancreas secrete what; what is the effect of this secretory product?
- VIP
- Induces glycogenolysis and hyperglycemia
- Stimulates GI secretions –> secretory diarrhea
Which value of HbA1C is considered diagnositc for diabetes?(≥
≥6.5%
A fasting plasma glucose of ≥ ______ mg/dL is considered diagnostic for diabetes.
A fasting plasma glucose of ≥ 126 mg/dL is considered diagnostic for diabetes.
A random plasma glucose ≥ ______ mg/dL is considered diagnostic for diabetes.
A random plasma glucose ≥ 200 mg/dL is considered diagnostic for diabetes.
What are 4 genetic syndromes associated w/ diabetes?
- Down syndrome
- Klinefelter syndrome
- Turner syndrome
- Prader-Willi syndrome
Fasting plasma glucose levels are determined primarily by what?
Hepatic glucose output
What is the major insulin-responsive site for postprandial glucose utilization and is critical for preventing hyperglycemia and maintaining glucose homeostasis?
Skeletal muscle
What 2 classes of drugs have been created for pt’s with T2DM based on the incretin effect?
- GLP-1 receptor agonists
- DPP-4 inhibitors (↓ breakdown of incretins)
Which form of diabetes is associated with amyloid deposition in pancreatic islets?
Type 2 DM
What are 2 mitogenic functions of insulin?
- Initiation of DNA synthesis in certain cells
- Stimulation of cell growth and differentiation
Insulin signaling facilitates the trafficking and docking containing which insulin-sensitive glucose transporter to the plasma membrane?
GLUT-4
What is the most important susceptibility locus associated with T1DM; what chromosome is it on?
HLA gene cluster on chromosome 6p21
Which 2 HLA loci are associated with T1DM?
- HLA-DR3
- HLA-DR4
Individuals with what concurrent HLA halotypes have the highest inherited risk for T1DM?
DR3 or DR4 concurrently w/ a DQ8
The classic manifestations of T1DM (hyperglycemia and ketosis) occur after more than _______% of the beta-cells have been destroyed
The classic manifestations of T1DM (hyperglycemia and ketosis) occur after more than 90% of the beta-cells have been destroyed
What is the fundamental immune abnormality underlying the pathogenesis of T1DM?
Failure of self-tolerance in T cells specific for islet antigens
What are the 3 circulating islet autoantibodies observed in the majority of pt’s with T1DM as well as asymptomatic family members at risk for progression to overt disease?
- anti-insulin
- anti-GAD
- anti-ICA512
Which type of diabetes (T1DM or T2DM) has a stronger genetic component?
T2DM —> disease concordance >90% in monozygotic twins
What are the 2 cardinal metabolic defects that characterize T2DM?
- ↓ response of peripheral tissues, especially skeletal m., adipose, and liver to insulin = insulin resistance
- Inadequate insulin secretion in the face of insulin resistance and hyperglycemia = β-cell dysfunction
Excess FFA’s within macrophages and β cells in the setting ↑ central obesity can activate what; contribute to insulin resistance how?
Inflammasome leads to secretion of IL-1β = release of pro-inflammatory cytokines —> insulin resistance
Maturity-onset diabetes of the young (MODY) resembles what type of diabetes?
T2DM
How does maturity-onset diabetes of the young (MODY) resemble T2DM?
- ↑ blood insulin
- NO autoantibodies
- NON-ketotic
Maturity-onset diabetes of the young (MODY) is most often associated with loss-of-function mutations in which gene?
Glucokinase (GCK)
Rare insulin receptor mutations which impair tissue response to insulin can cause what 2 disease states?
- Type A insulin resistance —> acanthosis nigricans
- Lipoatrophic diabetes —> hyperglycemia + loss of subcutaneous adipose tissue
Women w/ pregestational diabetes (where hyperglycemia was present before conception) have an increased risk for what fetal complications?
- Stillbirth
- Congenital malformations
Poorly controlled diabetes arising later in pregnancy, regardless of prior history, can lead to what problems for the infant?
- Excessive weight at birth (macrosomia)
- Problems later in life including obesity and diabetes
How is the diagnosis of T2DM most frequently made?
After routine blood testing in asymptomatic pt
Classic triad of T1DM?
- Polyuria
- Polyphagia, BUT losing weight!
- Polydipsia