Figure 1.

Time course of gelatinase activation in conditioned medium and cell extracts. Aliquots containing 10⁶ fibroblasts were incorporated into 2-ml collagen lattices at time 0. At the indicated times, culture medium was collected, and the lattices were washed and extracted as described. Equal volumes of conditioned medium and equal amounts of protein from cell extracts were then subjected to gelatin zymgography.