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Cellular respiration

Breaking down glucose (food) without oxygen to provide available energy for the cells. The glucose reacts with oxygen to produce energy in the form of ATP with carbon dioxide and water as waste products

Genetically modified

This indicates that an animal or plant has had its genetic makeup altered in some way. This is often by combining the genes from different organisms to produce an organism with desirable characteristics

Islets of Langerhans

Groups of pancreatic cells which make the hormones such as insulin which control the blood sugar levels.

Diabetes insipidus

A disease resulting from a lack of anti-diuretic hormone that causes the inability to retain water and produce concentrated urine in the kidneys.

Type 2 diabetes

The pancreas does produce insulin but cells stop responding properly to the insulin. It is often linked to obesity and lack of exercise and taking more exercise, losing weight and eating a carefully balanced diet can often control or even reverse type 2 diabetes.

Hyperglycaemia

Raised blood glucose levels (more than 10mmol/l)

Radiotherapy

Treatment of disease using X-rays or radioactive substances which kill cells

Hypothalamus

An area of the brain which regulates hormone release, temperature control, hunger, thirst and sleep.

Blood sugar

The sugar (glucose) dissolved in the blood; the normal range is 4.0 - 7.8 mmol/l

Receptors

Protein molecules attached to cells that only bind to specific molecules with a particular structure

Glucagon

A hormone produced by the pancreas. It causes the liver to convert glycogen back to glucose and to release glucose into the bloodstream.

Pancreas

An endocrine gland which produces insulin

Diabetes mellitus

A disease resulting from a lack of insulin production by the pancreas or a loss of the cell response to insulin that causes a loss of control of the glucose balance of the body.

Obesity

A disorder where an excessive amount of fat has accumulated in the body. It results when the energy taken in as food is stored in the body instead of being used up through activity

Hormone

A chemical messenger produced by a particular gland or cells of the endocrine system. Hormones are transported throughout the body in the blood stream but they produce a response only in specific target cells

Insulin

A hormone produced by the pancreas. It allows cells in the body to take in and store glucose.

Glucose

A type of sugar: a mono saccharide with 6 carbon atoms (a hexose sugar).

Kidney

Reddish brown organs which get rid of waste urea from the body and balance the water and mineral ion concentration of the blood

Gland

A group of cells which produce and secrete a particular substance. Many glands pass their secretions into a tube or duct, whereas endocrine glands secrete hormones directly into the blood.

Urine

The liquid which leaves your body through the urethra. It contains water, salts urea and other chemicals.

Antidiuretic hormone

Hormone produced in the hypothalamus that is produced by the pituitary gland when the body needs to lose less water. It affects the permeability of the distal convoluted tubule and the collecting duct of the kidney to water

Treating diabetes and other hormonal diseases

Human hormones are organic chemicals produced in specialised endocrine glands. They are released directly into the blood stream and are carried to their target organs in the blood. The cells of the target organs have specific receptors for the hormones. Hormones are involved in the coordination and control of many long term processes in the body such as growth and development. They are also involved in some rapid responses - for example controlling the levels of glucose in the blood and the ‘fight-or-flight’ response.

Hormonal diseases usually involve the problems that result when the body lacks a particular hormone or makes too much of one. The treatment will depend on whether the body has too little or too much of a particular hormone, and why.

Diabetes

Diabetes is not a single condition. Diabetes mellitus (or ‘sweet fountain’) is the most common form of diabetes. It involves the hormone insulin and affects the control of sugar levels in the blood. Diabetes insipidus (or ‘watery fountain’) involves the hormone ADH (antidiuretic hormone) and results in the production of large volumes of dilute urine. Again, untreated it can be fatal.

Hormonal control of blood sugar levels

The interaction of the hormones insulin and glucagon are key to the maintenance of the blood sugar levels of the body within normal limits

Treating diabetes mellitus

In treating diabetes the aim is to replicate, as closely as possible, the normal control of blood sugar levels.

There are two types of diabetes mellitus.

Type 1 diabetes usually affects people from childhood or early adulthood. It occurs when the Islets of Langerhans in the pancreas – the cells that usually produce insulin - fail. Without insulin, control of the blood glucose is lost. Glucose cannot be taken into the cells and so cannot be used in cellular respiration. This results in hyperglycaemia – a rise in the blood glucose levels that causes many problems for the body. Glucose is excreted in the urine. The raised levels of glucose in the blood and lack of glucose in the cells can, if untreated, be fatal. Treatment involves replacing the insulin by regular injections. The challenge for the medical profession is how to replicate the fine control of the natural systems. So far this isn’t possible – but techniques are improving all the time.

Originally the insulin needed was extracted from the pancreases of pigs and other animals slaughtered for meat. This had a number of associated problems – for example

  • it was not exactly the same as human insulin so some people were allergic to it
  • it had to be purified
  • the supply was linked to consumer demand for meat rather than the needs of people with diabetes for insulin.

Now genetically modified bacteria are used to produce human insulin. They are cultured in fermenters. The insulin produced is pure human insulin, and the supply of the drug can be tailored to the numbers of people who need it rather than the number of people wanting to eat meat.

Human insulin

Human insulin produced by genetically modified bacteria has revolutionised treatment for people with diabetes
(Photo credit: Benjah-bmm27, Wikimedia Commons)

It is important to enable people with diabetes to monitor and control their blood glucose as simply and accurately as possible

Finger prick blood tests to measure the blood glucose levels followed by insulin injections Photo of someone giving themselves an insulin injection Works well, but requires discipline from the patient. They must take care with their diet, avoiding too much carbohydrate food, check their blood glucose levels regularly, inject insulin a given time before eating and try to maintain a very regular routine.
Insulin pumps have a line into the body and supply short-acting insulin doses through the day
Photo of someone wearing an insulin pump

(Permission for use granted by Jayesh Mirpuri)

Gives relatively good control. There is more flexibility than with insulin injections. However there is the possibility of infection at the entry site to the body and there are more blood tests because the insulin delivered is very short acting.
Pancreas transplants replace the ineffective pancreas with one that produces insulin from a donor. Photo of pancreas ready for transplant surgery

(Photo credit: Herecomesdoc, Wikimedia Commons)

If a transplant works it restores normal function. There are not many pancreases available for transplantation. It requires major surgery and the recipient will need immunosuppressant drugs for life.
Stem cell transplants Image of stem cells

(Credit: Nissim Benvenisty)

The hope is that stem cells will be injected into the pancreas to produce functioning insulin-producing cells. This is still experimental but scientists are hopeful that in the future it may provide a cure for diabetes.

Type 2 diabetes is rather different. It tends to develop later in life, and it is strongly associated with obesity and lack of physical exercise. The pancreatic cells may produce less insulin than previously, but more often the body cells become less receptive to the effects of insulin.

The first line of treatment is usually for patients to lose weight and become more active – this alone can reverse many of the changes and remove the symptoms of diabetes. Only then will drugs be used.

Treating diabetes insipidus

People affected by diabetes insipidus can pass up to 20 litres of water in 24 hours. Unsurprisingly, they also feel constantly thirsty. In diabetes insipidus, either the hypothalamus of the brain no longer makes the hormone ADH, or the kidney tubules stop responding to ADH. ADH is the hormone needed to make the distal convoluted tubule and the collecting duct of the nephrons in the kidneys permeable to water, so it can be reabsorbed into the blood.

If your diabetes insipidus is caused by a lack of ADH, you may be given the drug desmopressin which has a similar effect on the kidneys as ADH and allows your body to conserve water. You may be given thiazide diuretics that concentrate the urine and so reduce the amount of water lost. NSAIDs or non-steroidal anti-inflammatory drugs such as ibuprofen also seem to help reduce the volume of urine produced – though scientists are not sure why!

If your kidney tubules do not respond to ADH, you may also be prescribed thiazide diuretics and NSAIDS, because they act on different mechanisms to conserve water and reduce the volume of urine produced.

More detailed information about the causes and treatment of diabetes can be found here.

Treating other hormonal conditions

There are many endocrine glands in the body. Common problems include:

  • Tumours that cause glands to grow, and to produce high levels of hormones. These may be treated in a number of ways:
    • surgically to remove excess tissue
    • radiotherapy to destroy excess tissue
    • chemical inhibitors that block the excess hormone
    in some cases the whole gland has to be removed or destroyed. In this case synthetic hormones are needed to replace the natural hormones that are lost
  • The biochemistry of cells may be disrupted so they produce too much or too little hormone. Too much: glands may be removed and synthetic hormones used as a replacement therapy, drugs that act as inhibitors either to a stage of the hormone synthesis pathway or to the hormone action on the cells may be supplied. Too little: drugs may be used to stimulate the glands or synthetic hormones may be supplied.
  • Compounds needed to produce the hormone may be lacking in the diet. In many cases, the missing element can be supplied and the glands will then function normally again. Sometimes synthetic hormones are needed to remove symptoms until natural production increases again.