Transforming growth factor beta regulates the metabolism of proteoglycans in bovine cartilage organ cultures.

The effect of transforming growth factor beta (TGF-beta) has been studied in a bovine articular cartilage organ culture. The peptide stimulates synthesis of proteoglycans in a dose-dependent manner, reaching saturation at 10 ng/ml. This dose gave an approximate 7-fold increase in synthesis over basal controls. In addition, the peptide decreased the rates of catabolism of proteoglycans with an approximately 2-fold maximal effect seen at 5 ng/ml. At the latter concentration, TGF-beta prevented the 4-fold loss of proteoglycans which occurred in cultures maintained under basal conditions over the course of 3 weeks. There was no increase in cell (DNA) content of the cartilage explants under these conditions of TGF-beta treatment, and the net collagen content of the explants remained constant.