[Study of the role of negative regulator, AcSer-Asp-Lys-Pro (AcSDKP) in the phenomena of cellular proliferation].

The intra and extracellular kinetics of AcSDKP levels in cell culture have been studied. A close correlation was observed between the minimal level of intracellular AcSDKP (a negative regulator of cell proliferation) and the initiation of DNA synthesis. The return to initial levels of intracellular AcSDKP when the rate of DNA synthesis decreases, suggests a role for the tetrapeptide in homeostasis during cell growth. The return to normal values was not observed in preliminary studies on cell lineages during uncontrolled proliferation.