Hormones

ADH (Vasopressin)

1. Anti-diuretic hormone acts to maintain blood pressure, blood volume and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney. 2. Anti-diuretic hormone helps to control blood pressure by acting on the kidneys and the blood vessels. Its most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in the urine. It does this by allowing water in the urine to be taken back into the body in a specific area of the kidney. 3. blood volume decrease or salt concentration in the blood stream increases. 4. Too much? High levels of anti-diuretic hormone cause the kidneys to retain water in the body. 5. Too little? Low levels of anti-diuretic hormone will cause the kidneys to excrete too much water.

Growth Hormone (GH)

1. Growth hormone is produced by the pituitary gland. It has many functions including maintaining normal body structure and metabolism. 2. acts on many parts of the body to promote growth in children. Once the growth plates in the bones (epiphyses) have fused growth hormone does not increase height. In adults, it does not cause growth but it helps to maintain normal body structure and metabolism, including helping to keep blood glucose levels within set levels. 3. Growth hormone release is not continuous; it is released in a number of 'bursts' or pulses every three to five hours. This release is controlled by two other hormones. 4. Too much? In adults, excessive growth hormone for a long period of time produces a condition known as acromegaly, in which patients have swelling of the hands and feet and altered facial features. These patients also have organ enlargement and serious functional disorders such as high blood pressure, diabetes and heart disease. Too little? Too little growth hormone (deficiency) results in poor growth in children. In adults, it causes a reduced sense of wellbeing, increased fat, increased risk of heart disease and weak heart, muscles and bones.

Thyroid stimulating hormone (TSH)

1. Its role is to regulate the production of hormones by the thyroid gland. 2. Thyroid stimulating hormone is produced and released into the bloodstream by the pituitary gland. It controls production of the thyroid hormones, thyroxine and triiodothyronine, by the thyroid gland by binding to receptors located on cells in the thyroid gland. Thyroxine and triiodothyronine are essential to maintaining the body's metabolic rate, heart and digestive functions, muscle control, brain development and maintenance of bones. 3. Too much? If a person has too much, this may indicate that their thyroid gland is not making enough thyroid hormone, that is, they have an underactive thyroid gland or hypothyroidism. People with an underactive thyroid often feel lethargic, experience weight gain and feel the cold. 4. Too little? If a person has too little thyroid stimulating hormone, it is most likely that their thyroid gland is making too much thyroid hormone, that is, they have an overactive thyroid or hyperthyroidism, which is suppressing the thyroid stimulating hormone. People with an overactive thyroid have the opposite symptoms to those with hypothyroidism, i.e. they lose weight (despite increasing the amount they eat), feel too hot and can experience palpitations or anxiety.

Prolactin

1. Produce in the anterior pituitary gland, also produces in other adipose tissues. 2. Responsible for Milk production. 3. Regulated by dopamine, produced in the hypothalamus. OESTROGEN. 4. Too much? caused by pregnancy medications that inhibits dopamine, hypothyroidism. 5. too little? Caused by pituitary under-activity

Oxytocin

1. Produced in the hypothalamus, and is secreted into the bloodstream by the posterior pituitary gland. 2. The two main actions of oxytocin in the body are contraction of the womb (uterus) during childbirth and lactation. 3. Regulated: by a positive feedback mechanism where release of the hormone causes an action that stimulates more of its own release. When contraction of the uterus starts, for example, oxytocin is released, which stimulates more contractions and more oxytocin to be released. In this way, contractions increase in intensity and frequency. 4. Too much? High levels have been linked to benign prostatic hyperplasia, a condition which affects the prostate in more than half of men over the age of 50. This may cause difficulty in passing urine. 5. Too little? in a nursing mother would prevent the milk-ejection reflex and prevent breastfeeding.

Testosterone

1. Testosterone is a hormone that is responsible for many of the physical characteristics specific to adult males. It plays a key role in reproduction and the maintenance of bone and muscle strength. 2. Testosterone is produced by the gonads (by the Leydig cells in testes in men and by the ovaries in women), although small quantities are also produced by the adrenal glands in both sexes. It is an androgen, meaning that it stimulates the development of male characteristics. 3. Regulation: In response to gonadotrophin-releasing hormone from the hypothalamus, the pituitary gland produces luteinising hormone which travels in the bloodstream to the gonads and stimulates the production and release of testosterone. As blood levels of testosterone increase, this feeds back to suppress the production of gonadotrophin-releasing hormone from the hypothalamus which, in turn, suppresses production of luteinising hormone by the pituitary gland. 4. Too much? The use of anabolic steroids (manufactured androgenic hormones) shuts down the release of luteinising hormone and follicle stimulating hormone secretion from the pituitary gland, which in turn decreases the amount of testosterone and sperm produced within the testes. 5. Too little? In adult men, low testosterone may lead to a reduction in muscle bulk, loss of body hair and a wrinkled 'parchment-like' appearance of the skin. Testosterone levels in men decline naturally as they age. In the media, this is sometimes referred to as the male menopause (andropause).

Thyroxine (T4 T3)

1. Thyroxine is the main hormone secreted into the bloodstream by the thyroid gland. It is the inactive form and most of it is converted to an active form called triiodothyronine by organs such as the liver and kidneys. 2. This hormone production system is regulated by a feedback loop so that when the levels of the thyroid hormones (thyroxine and triiodothyronine) increase, they prevent the release of both thyrotropin-releasing hormone and thyroid stimulating hormone. This system allows the body to maintain a constant level of thyroid hormones in the body. 3. too much? This may be caused by overactivity of the thyroid gland (hyperthyroidism), as in Graves' disease, inflammation of the thyroid or a benign tumour. intolerance to heat, weight loss, increased appetite, increased bowel movements, irregular menstrual cycle, rapid or irregular heartbeat, palpitations, tiredness, irritability, tremor, hair thinning/loss and retraction of the eyelids resulting in a 'staring' appearance. 4. too little? hypothyroidism. caused by autoimmune diseases, poor iodine intake or caused by the use of certain drugs. It can result in symptoms such as fatigue, intolerance of cold temperatures, low heart rate, weight gain, reduced appetite, poor memory, depression, stiffness of the muscles and reduced fertility

Gastrin

1. is a hormone produced by the stomach, which stimulates the release of gastric acid. 2. This allows the stomach to break down proteins swallowed as food and absorb certain vitamins. can stimulate the gallbladder to empty its store of bile and the pancreas to secrete enzymes. 3. Controlled: The production and release of gastrin is slowed by the hormone somatostatin, which is released when the stomach empties at the end of a meal and when the pH of the stomach becomes too acidic. 4. Too Much?: High levels of circulating gastrin can also occur when the pH of the stomach is high (i.e. not acidic enough) 5. Too Little: may increase the risk of infection within the gut and may limit the ability of the stomach to absorb nutrients.

Progesterone

1. is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. 2. During the menstrual cycle, when an egg is released from the ovary at ovulation (approximately day 14), the remnants of the ovarian follicle that enclosed the developing egg form a structure called the corpus luteum. This releases progesterone and, to a lesser extent, oestradiol. The progesterone prepares the body for pregnancy in the event that the released egg is fertilised. No Pregnancy: If the egg is not fertilised, the corpus luteum breaks down, the production of progesterone falls and a new menstrual cycle begins. Pregnancy: If the egg is fertilised, progesterone stimulates the growth of blood vessels that supply the lining of the womb (endometrium) and stimulates glands in the endometrium to secrete nutrients that nourish the early embryo. Progesterone then prepares the tissue lining of the uterus to allow the fertilised egg to implant and helps to maintain the endometrium throughout pregnancy. Controlled: The formation of the corpus luteum (which produces the majority of progesterone) is triggered by a surge in luteinising hormone (LH) production by the anterior pituitary gland. Too Little?: If progesterone is absent or levels are too low, irregular and heavy menstrual bleeding can occur. A drop in progesterone during pregnancy can result in a miscarriage and early labour.

Erythropoetin

1. is a hormone, produced mainly in the kidneys, which stimulates the production and maintenance of red blood cells. 2. Erythropoietin is a hormone that is produced predominantly by specialised cells in the kidney. Once it is made, it acts on red blood cells to protect them against destruction. At the same time it stimulates stem cells of the bone marrow to increase the production of red blood cells. 3. Controlled: When there is sufficient oxygen in the blood circulation, the production of erythropoietin is reduced, but when oxygen levels go down, the production of erythropoietin goes up. 4. Too Little? Amenia, caused by chronic kidney disease, there will be fewer red blood cells.

Estradiol

1. is a powerful reproductive hormone that has a wide range of actions in both men and women. 2. has many functions, although it mainly acts to mature and maintain the female reproductive system. 3. Controlled: The hypothalamus in the base of the brain releases a hormone called gonadotropin-releasing hormone. Gonadotropin-releasing hormone then acts on the pituitary gland to cause the release of two further hormones, luteinising hormone (LH) and follicle stimulating hormone (FSH). LH and FSH enter the blood and stimulate the ovary; in particular, LH and FSH act on the cells that surround each egg (these cells plus the egg form a unit called a follicle) stimulating the follicle to grow and develop. In the last stages of growth and development the cells surrounding the egg will produce oestradiol. After the egg has been ovulated, the ovulated follicle will become a corpus luteum. The corpus luteum produces both progesterone and oestradiol and the primary role of these two hormones is to ensure that the lining of the uterus is fully prepared for implantation, if fertilisation occurs. The amount of oestradiol (and progesterone) in the circulation communicates with the hypothalamus and pituitary to control the development of an egg, ovulation and the menstrual cycle.

Angiotensin 2

1. is a protein hormone that causes blood vessels to become narrower. It helps to maintain blood pressure and fluid balance in the body. 2. blood vessels (vascular), to cause constriction (narrowing) of the blood vessels and hence to increase blood pressure nerves (neurological), to cause the sensation of thirst, desire for salt, and to encourage the release of anti-diuretic hormone from the pituitary gland and noradrenaline from sympathetic nerves adrenal glands, to stimulate aldosterone production, resulting in the body retaining sodium and losing potassium from the kidneys the kidneys, to increase sodium retention and to alter the way the kidneys filter blood. This increases water reabsorption in the kidney to increase blood volume and blood pressure. The overall effect of angiotensin II is to increase blood pressure, body water and sodium content. 3. An increase in renin production occurs if there is a decrease in sodium levels and a decrease in blood pressure, which is sensed by the kidneys 4. Too Much? a common problem resulting in excess fluid being retained by the body and, ultimately, raised blood pressure. 5. Too little? Absence of angiotensin can be associated with retention of potassium, loss of sodium, decreased fluid retention (increased urine output) and low blood pressure.

Cortisol

1. is a steroid hormone that regulates a wide range of processes throughout the body, including metabolism and the immune response. It also has a very important role in helping the body respond to STRESS. 2. Controlled: The secretion of cortisol is mainly controlled by three inter-communicating regions of the body, the hypothalamus in the brain, the pituitary gland and the adrenal gland. 3. Too Much? Cushing's syndrome. high blood pressure osteoporosis skin changes (bruises and purple stretch marks) muscle weakness mood swings, which show as anxiety, depression or irritability increased thirst and frequency of urination. 4. Too Little: Addison's disease; fatigue, dizziness (especially upon standing), weight loss, muscle weakness, mood changes and the darkening of regions of the skin

Insulin

1. is an essential hormone produced by the pancreas. Its main role is to control glucose levels in our bodies. 2. The main actions that insulin has are to allow glucose to enter cells to be used as energy and to maintain the amount of glucose found in the bloodstream within normal levels. As glucose moves inside the cells, the amount of glucose in the bloodstream returns to normal and insulin release slows down. 3. Too Much?: cells will take in too much glucose from the blood. This leads to abnormally low blood glucose levels (called hypoglycaemia). The body reacts to hypoglycaemia by releasing stored glucose from the liver in an attempt to bring the levels back to normal. Low glucose levels in the blood can make a person feel ill. 4. Too little?: he patient's beta cells may have problems manufacturing insulin, so although some insulin is produced, it is not enough for the body's needs. Secondly, the available insulin doesn't work properly because the areas in the cell where insulin acts, called insulin receptors, become insensitive and stop responding to the insulin in the bloodstream.

Adrenocorticotropic hormone (ACTH)

1. is produced by the pituitary gland. Its key function is to stimulate the production and release of cortisol from the cortex of the adrenal gland. 2. Stress, both physical and psychological, also stimulates adrenocorticotropic hormone production and hence increases cortisol levels. 3. Secretion of adrenocorticotropic hormone is controlled by three inter-communicating regions of the body, the hypothalamus, the pituitary gland and the adrenal glands. 4. Too much? - Cushing's disease: It is caused by a non-cancerous tumour called an adenoma located in the pituitary gland, which produces excess amounts of adrenocorticotropic hormone - Addison's disease: 5. Too low: could lead to a poorly functioning adrenal gland due to insufficient production of cortisol.

Glucagon

1. is produced to maintain glucose levels in the bloodstream when fasting and to raise very low glucose levels. 2. It stimulates the conversion of stored glycogen (stored in the liver) to glucose, which can be released into the bloodstream. This process is called glycogenolysis. It promotes the production of glucose from amino acid molecules. This process is called gluconeogenesis. It reduces glucose consumption by the liver so that as much glucose as possible can be secreted into the bloodstream to maintain blood glucose levels. 3. Controlled: The release of glucagon is prevented by raised blood glucose and carbohydrate in meals, detected by cells in the pancreas. 4. Too Much?: caused by a tumor in the pancreas. 5. Too Little?: This results in severely low blood glucose which cannot be controlled without administering glucagon. Glucagon can be given by injection to restore blood glucose lowered by insulin (even in unconscious patients).

HCG (human chorionic gonadotropin)

Human chorionic gonadotrophin is a reproductive hormone that is essential for establishing and maintaining early pregnancy. 2. is produced by the trophoblast cells which surround the developing embryo at approximately day five of pregnancy. The amount of human chorionic gonadotrophin in the bloodstream doubles every 2-3 days as development of the embryo and placenta continue, and levels peak at around six weeks of pregnancy 3. Too much? Very high levels of human chorionic gonadotrophin are rare but can indicate hyper-proliferation of the placenta. 4. Too Little? Low levels of human chorionic gonadotrophin can indicate a failing pregnancy. Reduced levels of human chorionic gonadotrophin are often observed in ectopic pregnancies (where the embryo implants outside of the uterus) or in miscarriages.

Aldosterone

is a steroid hormone. Its main role is to regulate salt and water in the body, thus having an effect on blood pressure. 2. It plays a central role in the regulation of blood pressure mainly by acting on organs such as the kidney and the colon to increase the amount of salt (sodium) reabsorbed into the bloodstream and to increase the amount of potassium excreted in the urine. Aldosterone also causes water to be reabsorbed along with sodium; this increases blood volume and therefore blood pressure. Aldosterone is part of a group of linked hormones, which form the renin-angiotensin-aldosterone system. Activation of this system occurs when there is decrease in blood flow to the kidneys following loss of blood volume or a drop in blood pressure