The role of human growth hormoneGrowth hormone (GH) is made by the pituitary gland, which sits at the base of the brain.
Growth hormone is very important for development. It doesn’t just regulate normal human growth (height), but also has other
important metabolic functions, such as regulating blood sugar levels, fat distribution, muscle mass and muscle and bone strength.
Growth hormone is made in different amounts at different stages of life.
The body produces the most growth hormone during the teenage growth spurt, and then falls to around 25% of this level later
in life.
Growth Hormone Deficiency (GHD) can be grouped into 3 types:
Congenital: caused by a problem with the pituitary gland or hypothalamus during foetal development
Acquired: caused by damage to the pituitary gland or hypothalamus from tumours, severe head injury or infections such as meningitis
or encephalitis
Childhood GHD
Paediatric Growth Hormone Deficiency occurs during childhood when the body doesn’t produce enough growth hormone to ensure
normal growth. The result is that children who suffer from this condition are noticeably shorter in stature than other children
of the same age.
In normal children, GH works throughout the body to stimulate growth. Not having enough of this hormone affects the body’s
basic supplies for growth.
This lack has a number of consequences:
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Inability to make enough new proteins to build muscles, resulting in weakness and impact on the ability to exercise
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Failure to stimulate production of other hormones, such as insulin-like growth factor, which is especially important in stimulating
bone growth
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Failure to signal other parts of the body involved in growth
-
In children, lack of GH results in short stature, delayed maturation and inability to grow strong bones. In addition, the
face may remain childish and the child may accumulate increased fat particularly around the stomach area.
The earlier a treatable growth problem is detected, the better the child’s chance of achieving a normal height throughout
childhood and realising his or her full growth potential. In a society that places great emphasis on height, children who
are short for their age sometimes have problems because playmates and teachers treat them as though they are younger rather
than just smaller.
Other related growth disorders include:
Small for Gestational Age (SGA)
SGA is a term used to describe children who are born significantly smaller (either in weight or length, or both) than expected
for the length of time spent in the womb.
Babies born small for gestational age (SGA) as compared with other babies who had the same amount of time in the womb generally
grow extra fast in the first months of life; thanks to this ‘catch up’ growth, they often reach the same size as normal babies
by about 2 years of age. If this is not the case, extra GH can help SGA babies achieve normal adult height.
Turner Syndrome (TS)
Named after the endocrinologist Dr Henry Turner who first described the condition in 1938, Turner Syndrome is caused by a
genetic defect that occurs only in girls. Most girls are born with two female X chromosomes; in girls born with TS one of
the two X chromosomes is missing, incomplete or damaged. TS can cause growth disorders and short stature. Early GH therapy
has been shown to increase the rate of gain in height in girls with TS and may increase final adult height.
Chronic renal failure (CRF)
Also known as chronic kidney disease, CRF describes kidney malfunction that develops gradually over time (at least three months).
As CRF progresses, the kidneys become less able to remove wastes and extra water from the body. Children with CRF often have
poor growth and can be treated by GH.