GH (GROWTH HORMONE)

GROWTH HORMONE; GH

Growth hormone (GH) is a hormone that is essential for normal growth and development in children. It promotes proper linear bone growth from birth through puberty. In both children and adults, growth hormone helps regulate the rate at which the body both produces energy from food (metabolism) and makes lipids, proteins, and glucose (sugar). It also helps regulate the production of red blood cells and muscle mass.

Growth hormone is produced by the pituitary gland, a small gland located at the base of the brain behind the bridge of the nose. It is normally released into the blood in pulses throughout the day and night with peaks that occur mostly during the night. Because of this, a single measurement of the level of GH in blood is difficult to interpret and not usually clinically useful. The value will be higher if the sample is taken during a pulse and lower if it is taken during a period between pulses.Therefore, procedures called growth hormone stimulation and suppression tests are most often used to diagnose conditions caused by growth hormone deficiency or excess.

Some children have GH deficiency at birth (congenital), but some may develop a deficiency later due, for example, to a brain injury or tumor. These conditions can affect the pituitary gland, causing a decrease in pituitary function, resulting in a lowered production of pituitary hormones (hypopituitarism). Sometimes, the cause of the deficiency is not known, a category referred to as “idiopathic.”

Excess GH is most often due to a pituitary tumor (usually benign) that produces GH.Too much GH in children can cause their long bones to continue to grow beyond puberty, resulting in the extremely rare condition, gigantism, with heights of 7 feet or more. Those with excess GH may also have thickening of facial features, general weakness, delayed puberty, and headaches. Pituitary tumors releasing excess growth hormone can cause loss of vision if they grow very large.