By Dr Ananya Mandal, MD
Growth hormone is a vital hormone in the body that regulates growth, reproduction and regeneration processes. Growth hormone exerts its effects by acting on specific receptors present on the surface of cells.
Growth hormone and height
The height increase that occurs during childhood is the result of the effects of growth hormone. Two mechanisms are thought to stimulate this increase in height.
- Growth hormone binds to specific receptors on the surface of target cells, which activates the MAPK/ERK pathway. This causes the chondrocytes of cartilage to undergo cell division and multiply in number.
- Another mechanism of action involves the JAK-STAT signalling pathway, which stimulates the production of insulin-like growth factor 1 (IGF-1). In this context, GH acts mainly on the liver, where the IGF-1 is produced. IGF-1 stimulates the growth of various tissues and also stimulates osteoblast and chondrocyte activity to increase bone growth.
Other effects of growth hormone
Aside from increasing height, growth hormone has several other effects on the bodies of children and adolescents. Some of these include:
- Increasing protein synthesis
- Increasing muscle mass
- Promoting the breakdown of fats
- Increasing calcium retention and the increasing mineralization of bones
- Increasing growth of all organs except for the brain
- Reducing uptake of glucose by the liver
- Increasing gluconeogenesis in the liver
- Stimulating the immune system
- Maintaining function of the pancreatic islets
Reviewed by Sally Robertson, BSc
Last Updated: Jul 20, 2014