Glossary

Acetoacetic acid – see Ketone bodies.

Acetone – see Ketone bodies.

Autoimmunity – a process in which the body makes antibodies which destroy its own tissues. The types of cells most often affected are blood cells, glands and connective tissues such as joint linings.

Alpha cells – the cells in the Islets of Langerhans in the pancreas which produce glucagon.

Beta cells – the cells in the Islets of Langerhans in the pancreas which produce insulin.

Beta-hydroxybutyric acid – see Ketone bodies.

Body Mass Index (BMI) – a measure of obesity calculated by dividing the body weight by the square of the height [Read more about BMI].

Carbohydrate – molecule containing carbon, hydrogen and oxygen atoms in the ratio 1:2:1.

Carbohydrate, complex – carbohydrate molecule containing more than 2 monosaccharide units.

Carbohydrate, simple (sugar) – carbohydrate molecule containing 1 or 2 monosaccharide units.

Decilitre (dL) – one tenth of a litre.

Central obesity – a condition in which the Body Mass Index is greater than 30, and the distribution of the excess fat is mainly in the abdomen (belly fat).

Enzyme – a substance (usually a protein) which helps to speed up metabolic reactions.

Fasting Blood Glucose – a blood glucose measurement taken between 08.00h and 09.00h following a complete fast from midnight. Water is permitted for thirst. Normal medications are usually postponed until the sample has been taken.

Glucagon – a hormone produced by the alpha cells in the Islets of Langerhans in the pancreas. Glucagon plays a part in glucose metabolism, mainly causing release of glucose from stored glycogen in the liver.

Glutamic Acid Decarboxylase (GAD) – An enzyme involved in protein synthesis, one form of which (GAD 65) is found in the pancreas.
 
Glycated Hemoglobin – The US English version of Glycosylated haemoglobin.

Glycogen – a starchy substance made up of glucose molecules used to store glucose in the liver and muscles.

Glycosylated Haemoglobin (Glycated hemoglobin, HbA1C)– a form of haemoglobin which has glucose attached chemically to the haemoglobin molecule. Once the glucose is attached, it does not come off again. Since the red blood cells which contain the haemoglobin last about 3 months, the proportion of haemoglobin which is glycosylated reflects the average blood glucose level over this same period. [Read more about glycosylated haemoglobin].

HbA1C – see Glycosylated Haemoglobin.

Haemoglobin – a protein contained in the red blood cells, giving them their red colour, which caries oxygen from the lungs to the body tissues.

Hemoglobin – the US English version of haemoglobin.

Hyperglycaemia – an abnormally high level of glucose in the blood (Usually defined as more than 11mmol/L (200mg/dL)).

Hypoglycaemia – an abnormally low level of glucose in the blood (Usually defined as less than 3.5mmol/L (65mg/dL)). This can lead to unconsciousness and seizures.

Impaired Fasting Glucose (IFG) – a fasting venous plasma glucose level of 5.6 -6.9mmol/L (100-125mg/dL). [Read more about fasting blood glucose in Definitions of Diabetes]

Impaired Glucose Tolerance (IGT) – a venous plasma glucose level of 7.8-11.0mmol/L (140-199mg/dL) 120 minutes after a 75g oral glucose load. [Read more about impaired glucose tolerance in Definitions of Diabetes].

Insulin – a hormone produced by the beta cells of the pancreas, which has widespread metabolic actions on metabolism, particularly of glucose.

Insulinoma Associated Peptide-2 – a molecule associated with beta cells in the pancreas.

Insulin resistance – the condition in which normal amounts of insulin fail to produce a normal response from fat, muscle and liver cells. In fat cells, this results in breakdown of fat. In muscle and liver cells, failure of glucose uptake and storage of glycogen. When there is insulin resistance,  levels of insulin and glucose are both raised,  leading to metabolic syndrome and Type 2 diabetes.

Islet cells – cells found in the Islets of Langerhans in the pancreas. The islets contain alpha cells, which make glucagon, and beta cells, which make insulin.

Islets of Langerhans – see Islet cells.

Ketoacidosis – a biochemical condition in which the blood becomes dangerously acidic because of the formation of ketone bodies from fat and protein breakdown due to lack of insulin. This can lead to diabetic coma.

Ketone bodies – acidic compounds formed from fat and protein breakdown due to insulin deficiency. The three ketone bodies are acetone, acetoacetic acid, and beta-hydroxybutyric acid. It is acetone which causes the characteristic smell on the breath of someone with ketoacidosis.

LADA – see Latent Autoimmune Diabetes in Adults.

Latent Autoimmune Diabetes in Adults – a variant of diabetes occurring in adult life characterised by immune destruction of the beta cells of the pancreas and therefore insulin deficiency. It is currently thought that up to 15% of people diagnosed as having Type 2 diabetes really have LADA [Read more about LADA].

Maturity Onset Diabetes of the Young - an inherited variant of Type 2 diabetes found in  children and young adults [Read more about MODY]

Metabolic Syndrome – a combination of central obesity, hypertension, hyperlipidaemia, hyperglycaemia and insulin resistance. Metabolic syndrome is associated with Type 2 diabetes and particularly with arterial disease and heart attacks.
 
Microvascular - relating to small blood vessels, usually capillaries.  It is the damage to the lining of these small blood vessels which is largely responsible for the complications of diabetes in the eye, the nerves, and the kidneys.

Milligram (mg) – one thousandth of a gram.

Millimole (mmol) – one thousandth of a mole (the molecular weight of a substance in grams). For instance, the molecular weight of sodium chloride is 58 (made up of protons, neutrons and electrons). One mole of sodium chloride is therefore 58g.

MODY – see Maturity Onset Diabetes of the Young.

Monosaccharide – simple carbohydrate molecule usually containing 6 carbon, 12 hydrogen and 6 oxygen atoms.

Pancreas – an organ found in the upper part of the abdomen at the back on the left, which has two main functions. It makes amylase and other enzymes which are released into the bowel and digest different components of food, and from the alpha and beta cells in the Islets of Langerhans, it releases glucagon and insulin into the bloodstream.

Peptide – a molecule containing nitrogen, carbon, hydrogen and oxygen atoms. A "building block" of proteins.

The National Institute for Heath and Clinical Excellence – a statutory body set up by the UK government to evaluate the effectiveness and safety of drugs and treatments.

Obesity – a condition in which the Body Mass Index is greater than 30.

Oral Glucose Tolerance Test (OGTT) – a test in which the subject has blood glucose measurements made fasting and for 120-180 mins after taking 75g glucose in a drink. [Read more about glucose tolerance tests].

Renal threshold – the level of blood glucose above which glucose spills over into the urine.

Primary Care Trusts – the local organisational bodies of the UK National Health Service responsible for funding and managing health care in their area.

Random Blood Glucose – a blood glucose level taken at any time, without taking into account the time of day, the relation to meals, activity or medications.

Reaven’s Syndrome – see Metabolic Syndrome.

Saccharide – carbohydrate molecule.

Syndrome X – see Metabolic Syndrome.

Type 1 diabetes – also known as juvenile onset diabetes or Insulin Dependent Diabetes (IDDM). [Read more about Type 1 diabetes]. Type 1 diabetes is characterised by failure of the beta cells in the Islets of Langerhans in the pancreas to produce insulin.

Type 2 diabetes – also known as maturity onset diabetes or Non-Insulin Dependent Diabetes (NIDDM)  [Read more about Type 2 diabetes]. Type 2 diabetes is characterised by insulin resistance, although this is almost always accompanied by progressive failure of the beta cells of the pancreas to make insulin.