Effect of pH on the induction of competence and progression to the S‐phase in mouse fibroblasts

Abstract
The pH dependence of competence induction and progression to the S‐phase in quiescent stimulated cells has been studied. The results show that: (i) induction of competence by fibroblast growth factor in these cells is relatively independent of the external pH between pH 5.6–7.6; (ii) progression of cells to the S‐phase is highly sensitive to pH and shows a dramatic increase between pH 6.8–7.2. These observations suggest that the intracellular alkalinization triggered by growth factors is fundamental for progression but not for competence induction.