Regulation of growth of fibroblasts.

Present knowledge on regulation of fibroblast growth is based on in vitro culture of fibroblasts from different sources. The research has focused on 2 problems: identification of the signal that reaches the fibroblast from outside and tells it to grow and identification of metabolic reactions inside the cell that commit it to initiate DNA synthesis after the signal arrives. Although the signal and the metabolic reactions have not yet been clearly identified, and the relationship between in vivo conditions and the result of these in vitro studies still has to be determined, the large body of data collected so far and the steadily growing information concerning these problems suggest a complex interrelation between cellular environment and metabolic processes involved in growth regulation.