Quiescent fibroblasts in a cellular model system.

Quiescent fibroblasts are non-dividing cells in a reversible postmitotic state induced by lowering the serum concentration of the medium (e.g. from 10% to 0.3%). Three to seven days after lowering the serum concentration only minor metabolic changes will take place in the cells. During this period the quiescent fibroblasts can be used experimentally in a model system for various periods of time.