Diabetes mellitus

Question 1

Glucose regulation

Answer 1

Food ingestion leads to release of gastrointestinal peptides (GLP-1 and GIP) and pancreatic hormones (insulin and amylin)
Insulin stimulated by high glucose and inhibited by glucagon
Glucagon stimulated by low glucose and inhibited by insulin

Question 2

Insulin

Answer 2

Produced by beta cells of islets of Langerhans in pancreas
A and B chains linked by disulphide bonds
Pre-proinsulin cleaved to proinsulin
C-peptide cleaved from pro-insulin prior to release

Question 3

Action of insulin

Answer 3

Anabolic hormone
Glucose transport into muscle and fat cells
Glycogen synthesis
Inhibits gluconeogenesis
Inhibits lipolysis
Stimulates cell growth

Question 4

Diabetes symptoms

Answer 4

Polydipsia (drinking more fluid)
Polyuria (passing more urine)
Weight loss
Blurred vision
Excessive tiredness

Question 5

Diabetes classification

Answer 5

Type 1 is juvenile onset
Autoimmune destruction of islet cells
Auto-antibodies ICA, GAD, IA-2
Type 2 is maturity onset
Insulin resistance (does not cause diabetes alone)
Beta-cell failure
Type 3 is secondary (pancreatitis, pancreatic cancer)

Question 6

Type 1 genetics

Answer 6

85% of patients have no affected 1st degree relative
30% risk if both parents have the condition
30-70% risk for an identical twin

Question 7

Type 1 environmental factors

Answer 7

Viruses such as Epstein-Barr may cause type 1. Exposure at young age may also decrease risk
Diet
Lifestyle. Exposure to toxins, stress

Question 8

Type 2 diabetes

Answer 8

Presents in middle age or elderly
Polygenetic. Often with a family history
Strongly linked to obesity and hypertension
Insulin resistance and inadequate production to overcome resistance

Question 9

Cause of type 2 resistance

Answer 9

Genetic factors. Islet cell development.
Insulin release
Abnormal receptor and signalling proteins
Environmental. Obesity
Diet
Age

Question 10

Thrifty genes

Answer 10

Evidence of thrifty genotype becoming susceptibility genotype in Pima Indians
Traditional life involves fat-poor diet and physical activity
New sedentary lifestyle with diet high in animal fat increased diabetes

Question 11

Obesity and inflammation

Answer 11

TNF-alpha is pro-inflammatory cytokine.

CXCL5 is pro-inflammatory and expressed in high levels in adipose tissue

Question 12

Type 1 toxins

Answer 12

Arsenic in water and BPA in bottles may increase risk