Multiplication-stimulating activity (MSA) and cartilage-derived factor (CDF): biological actions in cultured chondrocytes.
Previously, we showed that a polypeptide isolated from fetal bovine cartilage stimulates proteoglycan synthesis, RNA synthesis, and DNA synthesis in cultured rabbit costal chondrocytes. In the present study, the effects of the cartilage-derived factor (CDF) were compared with those of multiplication-stimulating activity (MSA), which is thought to be included in somatomedins. CDF and MSA markedly increased [3H]thymidine incorporation into rabbit costal chondrocytes from 7--14 h after their additions. The incorporation of [3H]uridine was also increased within 1--2 h in the cells incubated with the peptides. These stimulations of nucleic acid syntheses were followed by cell division in serum-free culture medium. On the other hand, the peptides enhanced the synthesis of sulfated proteoglycans within 7 h. Furthermore, the extent of stimulation of proteoglycan synthesis, as measured in terms of increased incorporation of [35S]sulfate, [3H]glucosamine, or [3H]serine into material precipitated with cetylpyridinium chloride, was consistently higher than the extent of CDF or MSA stimulation of total protein synthesis, as measured in terms of increased incorporation of [3H]serine into acid-insoluble cellular material. These findings suggest that the stimulation of proteoglycan synthesis by CDF and MSA is not directly linked to the peptide-induced stimulation of cell proliferation. The present study also showed that CDF is as effective as MSA in stimulating various metabolic indices in cultured chondrocytes at their optimal concentrations.
D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000378:metabolism*; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D007335:Insulin-Like Growth Factor II; D008297:Male; D010455:Peptides / Q000502:physiology*; D011506:Proteins / Q000502:physiology*; D011509:Proteoglycans / Q000096:biosynthesis; D012313:RNA / Q000096:biosynthesis; D011817:Rabbits
D010455:Peptides; D011506:Proteins; D011509:Proteoglycans; D012313:RNA; D007335:Insulin-Like Growth Factor II; D004247:DNA