Diabetes

Diabetes Mellitus is a group of conditions in which there is a deficiency of the hormone insulin or an insensitivity to it. Insulin is produced in the islet cells of the pancreas and is normally responsible for controlling blood concentrations of the body's main fuel, glucose. In normal animals, insulin does this by preventing glucose production by the liver and ensuring that excess glucose derived from food which is not needed for energy is put into body stores.

In a diabetic animal there is insufficient insulin to switch off glucose production by the liver or to efficiently store excess glucose derived from energy giving foods. This means that the blood concentration of glucose rises and eventually exceeds a level beyond which the kidneys let glucose leak into the urine. This loss of glucose in urine takes water with it by a process called osmosis and causes larger volumes of urine to be produced than normal.

The excessive loss of water in urine is compensated for by thirstiness and increased water consumption. The principal clinical signs of an animal with diabetes mellitus are therefore excessive urination and excessive water consumption. In addition, diabetic animals tend to lose weight because they breakdown stores of fat and protein (muscle) to make glucose and ketones (an alternative fuel) in the liver. Other clinical signs of diabetics may include: cataracts, increased appetite, exercise intolerance and recurrent infections. If the production of ketones by the liver is excessive a condition called ketoacidosis occurs which makes the animal very unwell.