What are the types of growth factors?

Some examples of growth factors include insulin-like growth factors (IGF), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), nerve growth factor (NGF), and VEGF. IGF stimulates growth by mediating the secretion of growth hormone from the pituitary gland. 

• IGF-1 and growth hormones promote normal growth of bones and tissues. 
• EGF is a single polypeptide of 53 amino acid residues which stimulate the growth of epithelial cells. EGF binds to the plasma membrane located in the EGF receptor. 
• PDGF stimulates the growth of muscle and connective tissue cells. 
• NGF is an insulin-like protein which regulates growth, development, and maintenance of embryonic and sympathetic sensory neurons. 
• VEGF promotes the growth of new blood vessels (angiogenesis). VEGF forms part of the mechanism which replenishes the blood supply to tissues and cells when they are in need of oxygenated blood due to compromised blood circulation.