title: The effects of lanthanum on the ultrastructure of hypertrophic chondrocytes and the localization of lanthanum precipitates in condylar cartilages of rats fed on normal and rachitogenic diets.
abstract: Ionic lanthanum was used to examine the distribution of calcium-binding sites in the condylar cartilages of rats that had been fed on normal and/or vitamin D-deficient rachitogenic diets for 4 weeks. Certain specific changes in the ultrastructure of the cartilage were attributed to the presence of the trivalent cation in the fixation medium. Cartilages from the rachitic animals showed a marked reduction in the quantity of lanthanum deposition on the outer surface of the chondrocytes and in the extracellular matrix. Returning rachitic rats to the control diet resulted in a corresponding return to a normal ultrastructural distribution of lanthanum in the condylar cartilages. No intracellular lanthanum deposits were observed. The results suggest that a vitamin D-dependent calcium-binding component may be an integral part of the chondrocyte plasma membrane structure.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002356:Cartilage / Q000378:metabolism* / Q000648:ultrastructure*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D006965:Hyperplasia; D007811:Lanthanum / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D012279:Rickets / Q000378:metabolism* / Q000473:pathology; D014807:Vitamin D / Q000494:pharmacology
chemical_list: D014807:Vitamin D; D007811:Lanthanum; D002118:Calcium