Regulation of stromal cell collagenase production in adult rabbit cornea: in vitro stimulation and inhibition by epithelial cell products.

Media conditioned by epithelial cells from the adult rabbit cornea were capable of both stimulating and inhibiting production of latent collagenase by stromal cells from the same source. Cytochalasin B was required in this in vitro system for both secretion of stimulators by epithelial cells and production of collagenase by stromal cells in response. Optimal production of collagenase by stromal cells in response. Optimal production of stimulators occurred in low-density epithelial cell cultures. Chromatographed conditioned medium from such cultures contained three stimulator fractions with apparent molecular weights of 19,000, 54,000, and greater than or equal to 90,000. High-density epithelial cell cultures secreted inhibitors of stromal cell collagenase production with apparent molecular weights of 7000 and 19,000. Cytochalasin B was not required for production of inhibitors. Inhibitory conditioned medium blocked the effect of the 19,000-dalton and 54,000-dalton stimulator on stromal cells. The data suggest that epithelial cells, in ways depending on their density, may modulate collagen degradation in the integument.