Control of blood glucose

Normal glucose levels are kept within strict limits

Glucose regulation in healthy people

• Kick-in when blood glucose levels deviate 20% from set-point

Key players in glucose homeostasis

• Pancreas (α and β cells: Islets of Langerhans)

• Liver• Muscles• Fat• (all tissues…)

• Insulin• Glucagon• (adrenaline)• (steroids)• (growth hormone)

Management of plasma glucose levels

Insulin and glucagon are synthesised in the pancreas

Hormones act on:• Liver• Muscle• Fat• Brain

Insulin optimises glucose uptake by cells

NB: The BRAIN and the LIVER don’t need GLUT4 for glucose uptake

Insulin is an anabolic hormone• Primary targets of insulin are liver, fat and muscle cells (but

acts on all tissues)• Drives glucose into cells, promotes glucose uptake by muscle,

fat and other tissues through facilitated diffusion (GLUT4 protein channel).

• Stimulates conversion of glucose to glycogen in liver and in muscles

• Inhibits fat breakdown (promotes fat synthesis)• Stimulates amino acid uptake and protein synthesis• Insulin receptors in the hypothalamus promote satiety: the

appetite centre has an insulin-driven ‘off’ button…

Glucagon release is stimulated by LOW plasma glucose

Released from alpha cells in response to:• Low plasma glucose• Protein-rich meal (high

levels of aa’s in blood)• Exercise

Glucagon is a catabolic hormone: released when glucose levels are LOW

Additional effects of glucagon

• Liver breaks glycogen down into glucose• Gluconeogenesis occurs from building blocks

in the liver• Mild promotion of fat breakdown• Also involved in appetite regulation in the

hypothalamus

Glucose regulation in healthy people

• Kick-in when blood glucose levels deviate 20% from set-point

Diabetes

Symptoms of diabetes

Type 1• 10% of diabetes

patients• ‘Childhood diabetes’1. Toilet2. Thirst3. Thinner4. Tired

Type 2• 90% of diabetes patients• May be influenced by

obesity• May be influenced by

genetic factors• May be slow onset

symptoms• Often undiagnosed for

up to 10 years

Complications of diabetes

There are many serious potential complications of chronic diabetes, including:• Chronic skin infections• Eye problems and potential blindness from

glaucoma (bui;ld up of pressure in the eye)• Nerve damage (often leads to amputations)• High blood pressure, leading to strokes, heart

attacks, kidney damage…

Management of Type 1 diabetes

• Insulin treatment• ‘Islet ‘ transplants• ‘Vaccine’ to prevent auto-immune destruction

of the pancreas

Management of type 2 diabetes

• The first-line of treatment is WEIGHT LOSS, dietary control and exercise

• Recommended diets are high fibre, low fat• …’diabetes superfoods’….