Wiktionary
n. A naturally-occurring substance capable of stimulate cellular growth, proliferation, and cellular differentiation.
WordNet
n. a protein that is involved in cell differentiation and growth
Wikipedia
A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation, healing, and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes.
Growth factors typically act as signaling molecules between cells. Examples are cytokines and hormones that bind to specific receptors on the surface of their target cells.
They often promote cell differentiation and maturation, which varies between growth factors. For example, bone morphogenetic proteins stimulate bone cell differentiation, while fibroblast growth factors and vascular endothelial growth factors stimulate blood vessel differentiation ( angiogenesis).
Usage examples of "growth factor".
From Hong's comments, it seemed to Jason that Hayes had probably been isolating some kind of growth factor which would stimulate growth, or differentiation, or maturation, or all three.
Then you ultrasonically inject a weekly dose of fibroblast growth factor, plus a few cells from the knuckle and the nail, at the appropriate times .
The Dewar flasks have the laminin and the nerve growth factor, both labeled.
Later on I checked and found that vascular endothelial growth factor made the body build bypass blood vessels to reroute the circulation around the vessel damaged by the clot.
The audio track, its pitch adjusted to run at just less than twice the standard playback speed, was part of a month-old newscast detailing potential military uses of a substance known as HsG, a biochemical governing the human skeletal growth factor.