GH (growth hormone), better known as growth hormone, has as its main function that of stimulating the development of the human organism. It is a protein hormone composed of a sequence of 191 amino acids, that is, molecules aggregated in long chains that serve to form proteins. Scientists who carefully measure overall GH production report that it increases during childhood, with peaks during puberty and decline from middle age onwards.
The first effect of growth hormone, as we have seen, is precisely that of promote growth. The effect of growth hormone is defined as an “anabolic” complex, that is, it stimulates the construction of tissues, organs and the organism as a whole.
This hormone acts on bones, cartilages, muscles and liver through the production of particular substances, called somatomedins (IGF1: insulin-like growth factor), responsible for bone growth; or it intervenes directly on the tissues producing metabolic effects such as the increase of triglycerides and glucose in the blood and the synthesis of proteins in the tissues. The final effect, therefore, is to stimulate the “construction” of tissues and organs.
The main function of growth hormone is to regulate growth in height. The stimulating action on growth begins at birth and ends after the welding of the cartilages present at the ends of the long bones. In young children, levels of growth hormone production are usually low, gradually increasing during childhood until reaching a peak during puberty that coincides with the period of fastest growth.
GH performs important functions no longer linked to growth but to the control of the metabolism of sugars, fats and proteins. In adulthood, GH levels in the blood progressively decrease.
Reduced or absent production of GH hormone (deficiency) can cause in children:
while in adults it can cause:
- reduction in bone density or muscle strength
- decreased metabolic response to stress, such as hypoglycemia (decreased blood glucose)
- high levels of fat in the blood
A GH deficiency can be caused by dysfunction in the hypothalamus; of the pituitary gland; target organs such as the liver (resulting in a defect in the production of somatomedins).
The growth of children must be monitored at least once a year to recognize short stature and also a change in the rate of growth.
In the presence of short stature and a significant slowdown in the child’s growth rate, it is advisable to:
- Check for various non-endocrine causes of short stature (e.g. celiac disease);
- Intensify the checks at the treating physician in case of demonstrated slowing of the growth rate.
GH deficiency therapy uses a biosynthetic hormone quite identical to that produced by the pituitary gland.
The purpose of the processing is therefore to:
- Ensure adequate final height;
- Ensure good development of both skeletal and cardiac muscle mass;
- Avoiding the child the psychological discomfort deriving from short stature;
- Reduce the risk of cardiovascular mortality in adulthood.
The duration of therapy depends on the severity of the hormonal defect. In most cases it is stopped 2-3 years after the completion of pubertal development.
Excessive GH production can cause in children:
- gigantism, i.e. an exaggerated height development compared to individuals of the same race and age
- delay in the development of the genitals and puberty
in adults it can cause:
- acromegaly, abnormal enlargement of the bones of the hands and feet and change in facial features, sometimes very noticeable
Article sources: Bambino Gesù Children’s Hospital, Higher Institute of Health (ISS)