The site of cartilage matrix degradation.

1. A 'cavity' organ culture method was developed, which allowed the insertion within bovine nasal cartilage of 10 microliter of 35S-labelled proteoglycan aggregate. 2. Stimulation of the tissue with retinol or catabolin led to degradation of both the cartilage matrix and the proteoglycan within the cavity. 3. Proteoglycan aggregate trapped in polyacrylamide beads was not broken down in the cavities of living cartilage, except under autolytic conditions. 4. It is suggested that degradation of proteoglycan aggregate by chondrocytes occurs in a pericellular region.