In normal cell function messenger chemicals, such as various growth factors and insulin, bind to protein receptors on the cell's surface. (newscientist.com)
By treating these with various growth factors, they were able to coax them into becoming cells that make EPO. (newscientist.com)
According to one hypothesis, the stem cells mature into fully - mature neurons that communicate with the threatened brain tissue; according to another, the stem cells secrete various growth factors that affect the host neurons. (sciencedaily.com)