title: Proteoglycan synthesis by sternal chondrocytes perturbed with vitamin A.
abstract: Proteoglycan synthesis by sternal chondrocytes was studied in the presence of excess vitamin A (10 i.u./ml). Proteoglycans synthesized by the treated cells were smaller, and had larger amounts of chondroitinase ABC-resistant materials than control cells. Vitamin A-pretreated cells, when provided with normal feeding medium, failed to revert back to normal morphology and synthetic processes. Chondrocyte cultures prelabelled with [35S]-sulphate, when maintained in the presence of excess of vitamin A, showed: (1) increased release of labelled proteoglycans into the medium, and (2) increased (19%) degradation of the proteoglycans. The proteoglycans synthesized by the vitamin A-treated chondrocytes are also incapable of binding with exogenous large molecular weight hyaluronic acid. Thus, high levels of vitamin A modulate the differentiation of chondrocytes by altering cellular synthetic processes.
mesh_terms: D000818:Animals; D002356:Cartilage / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D002850:Chromatography, Gel; D011509:Proteoglycans / Q000096:biosynthesis*; D013249:Sternum / Q000196:embryology; D014801:Vitamin A / Q000494:pharmacology*
chemical_list: D011509:Proteoglycans; D014801:Vitamin A