Type 2 diabetes
- Mechanism
In type 2 diabetes the body's cells stop listening to insulin, and over time the pancreas cannot keep up. Extra weight is the main driver.
What it is
Type 2 diabetes results from two defects: insulin resistance, mostly from central obesity, and beta-cell dysfunction that fails to compensate. Genetics matter, as shown by high concordance in identical twins and many risk loci, but environmental factors, mainly excess calories and inactivity, decide who gets it. It accounts for the great majority of diabetes worldwide and in Latin America.
Structure
- Islets: deposition of amyloid (from islet amyloid polypeptide) in the islet capillaries and between cells.
- Modest reduction of beta-cell mass, less than in type 1.
- Liver: steatosis (MASLD) is common.
Step by step
- Central adipose tissue expands and releases more free fatty acids and pro-inflammatory cytokines, less adiponectin.
- In muscle and liver, lipid metabolites and inflammatory kinases impair insulin receptor signalling (IRS serine phosphorylation).
- Muscle takes up less glucose; the liver keeps making glucose: blood glucose rises.
- Beta cells compensate with hyperinsulinaemia for years.
- Under chronic glucose and fat excess, with amyloid deposition and genetic weakness, beta cells fail: overt diabetes.
Clinical notes
- Often asymptomatic for years; found by screening or by complications.
- Rising in adolescents with obesity.
- Weight loss and exercise improve insulin sensitivity; metabolic surgery can induce remission.
Test yourself
Think of the answer, then tap the question to see it.
How do free fatty acids cause insulin resistance?
Their metabolites activate kinases that phosphorylate IRS proteins on serine residues, weakening insulin receptor signalling.
What is deposited in the islets in type 2 diabetes?
Amyloid derived from islet amyloid polypeptide (amylin).
Which adipokine improves insulin sensitivity and falls in obesity?
Adiponectin.
Elsewhere in DurgiPedia
- Obesity: leptin, adipokines and its consequences
- Insulin signalling
- Insulin receptor
- Islets and insulin: secretion and actions
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Diabetes Type 2 (MedlinePlus, US National Library of Medicine, 2025); Type 2 diabetes (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.