What is the difference between hgh and gh

A critical concept in understanding growth hormone activity is that it has two distinct types of effects:. Keeping this distinction in mind, we can discuss two major roles of growth hormone and its minion IGF-I in physiology. Growth is a very complex process, and requires the coordinated action of several hormones. The major role of growth hormone in stimulating body growth is to stimulate the liver and other tissues to secrete IGF-I.

IGF-I stimulates proliferation of chondrocytes cartilage cells , resulting in bone growth. Growth hormone does seem to have a direct effect on bone growth in stimulating differentiation of chondrocytes. IGF-I also appears to be the key player in muscle growth.

It stimulates both the differentiation and proliferation of myoblasts. It also stimulates amino acid uptake and protein synthesis in muscle and other tissues.

Growth hormone has important effects on protein, lipid and carbohydrate metabolism. In some cases, a direct effect of growth hormone has been clearly demonstrated, in others, IGF-I is thought to be the critical mediator, and some cases it appears that both direct and indirect effects are at play.

Production of growth hormone is modulated by many factors, including stress, exercise, nutrition, sleep and growth hormone itself. However, its primary controllers are two hypothalamic hormones and one hormone from the stomach:.

Growth hormone secretion is also part of a negative feedback loop involving IGF-I. High blood levels of IGF-I lead to decreased secretion of growth hormone not only by directly suppressing the somatotroph, but by stimulating release of somatostatin from the hypothalamus.

Growth hormone also feeds back to inhibit GHRH secretion and probably has a direct autocrine inhibitory effect on secretion from the somatotroph. 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.

This release is controlled by two other hormones that are released from the hypothalamus a part of the brain : growth hormone-releasing hormone , which stimulates the pituitary to release growth hormone, and somatostatin , which inhibits that release. Growth hormone levels are increased by sleep, stress, exercise and low glucose levels in the blood. They also increase around the time of puberty.

Growth hormone release is lowered in pregnancy and if the brain senses high levels of growth hormone or insulin-like growth factors already in the blood.

Not surprisingly, too much growth hormone causes too much growth. 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.

This condition is more common after middle-age when growth is complete so affected individuals do not get any taller. Very rarely, increased growth hormone levels can occur in children before they reach their final height, which can lead to excessive growth of long bones, resulting in the child being abnormally tall. This is commonly known as gigantism a very large increase in height. Overproduction of growth hormone is diagnosed by giving a sugary drink and measuring the growth hormone level over the next few hours.

The sugar should cause growth hormone production to reduce. However, this does not happen in acromegaly. 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.

Some children lack sufficient natural growth hormone to grow to their full height. Taking synthesised growth hormone can help them reach their full height. However, research suggests that a child with normal levels of growth hormone, who takes the synthesised version, will not grow any taller than they would have naturally, unless they take very large amounts. Children who are experiencing stunted or slowed growth should have their natural growth hormone levels checked by medical professionals before they are prescribed any medication for their condition.

Adults with growth hormone deficiency which may result from problems with the pituitary gland or hypothalamus may have symptoms including:. Approximately one third of people who use synthetic growth hormone will experience side effects.

These may include:. Acromegaly is a disorder caused by excess levels of growth hormone, most commonly as a result of a tumour in that person's pituitary gland. It causes an irreversible overgrowth of bones, particularly those of the face, hands and feet.

The person's skin is also affected and becomes thick, coarse and hairy. Other side effects include high blood pressure and heart disease. If the tumour occurs in childhood, then increased height may occur leading to gigantism. Long-term use of synthetic growth hormone can also cause acromegaly, but not gigantism. This is because it is impossible for an adult to grow taller using synthetic growth hormone. The ends of the long bones epiphyses in the mature skeleton are fused in adults.

High doses of growth hormone can only thicken the person's bones rather than lengthen them. Any increase in muscle size due to use of synthetic growth hormone is actually the result of an increase in connective tissue, which does not contribute to muscle strength. For this reason, use of synthetic growth hormone does not lead to increase muscle strength. In fact, in the long term, muscle weakness including weakness of the heart can be a result. In the past, growth hormone used to treat people was extracted, at autopsy, from the pituitary glands of people who had died.

In some countries not including Australia , it was discovered that a progressive and incurable disease of the brain called Creutzfeldt-Jakob disease CJD , which results in dementia and death, was in rare cases transmitted by this method.

Nowadays synthetic growth hormone is used, and there is no risk of CJD. Some athletes or bodybuilders who abuse growth hormone in an attempt to gain muscle size and strength also use other medications or illicit drugs to speed up their physical transformation. The dangers of mixing these different chemicals are not fully known. Some of the substances people may use include:. Giving up synthetic growth hormone can be extremely difficult for adults whose positive body image depends on looking large and muscular.