The role of epithelium and mesenchyme in the production of a collagenolytic enzyme and a hyaluronidase in the anuran tadpole

Abstract

Remodeling of connective tissue, occurring during amphibian metamorphosis involves the degradation of both collagen fibers and interfibrillar ground substance. The formation of a collagenolytic enzyme by the epithelial cells and the release of a hyaluronidase by the mesenchyme have been demonstrated in cultures of the separated tissue components. Puromycin (which has no direct effect on collagenase) as well as freeze-thawing block the appearance of collagenolytic activity, suggesting either de novo synthesis of collagenase or, alternatively, its activation by some mechanism requiring protein synthesis. Hyaluronidase activity, however, is not inhibited by puromycin and is enhanced by freeze-thawing, indicating that this enzyme is stored in the mesenchymal cells and probably released when needed. A mechanism for connective tissue resorption is proposed in which two different cell types cooperate, each providing a different enzyme capable of attacking extracellular structures in a specific manner.