title: The effect of experimental hypothyrosis on the fine structure of the epiphyseal cartilage of young rats.
abstract: Authors studied the effect of hypothyrosis induced by thyro-parathyroidectomy and mercaptoimidazole treatment on the fine structure of the proximal epiphyseal cartilage of tibia in growing male rats. It has been established that the cell density of the epiphyseal cartilage decreases in the experimental hypothyrosis, about 30 to 50% of the chondrocytes display degenerative signs, whereas the Golgisystem seems to be well developed. The most characteristic alteration appear in the zones of proliferation and maturation of the epiphyseal cartilage. The endoplasmic reticulum (ER) and mitochondria show a considerable regression also in the chondrocytes displaying minimal or even no signs of degeneration. Elements indicating calcification were encountered more frequently in the cartilaginous matrix of the zones of maturation and calcification under the effect of mercaptoimidazole treatment as compared to the controls, whereas the matrix of the animals operated was poorer in minerals than the corresponding zones of the controls. This difference is attributed by the authors to the different levels of thyrocalcitonin in the two kinds of experiments.
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000648:ultrastructure*; D004838:Epiphyses / Q000648:ultrastructure*; D007037:Hypothyroidism / Q000473:pathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains