Renal morphology in pigs with experimental hyperparathyroidism. Ultrastructural findings

Ultrastructural examinations were performed in three groups of pigs; one sham-operated control group, one group subjected to thyroidectomy, and another group injected with parathormone after thyroidectomy (TX + PTH). Attention was mainly paid to the localization and structural details of the calcium deposits which were found in the TX + PTH group 78 and 150 hours after the first PTH injection. Calcium deposits were found in the epithelial cells and lumina of the tubular system, especially in the proximal convoluted tubules. It is suggested that calcium first is deposited in mitochondria and cytoplasmic vacuoles and that larger calcific bodies, occasionally with concentric lamellation, are formed by coalescence of small calcific particles, and that the calcium deposits induce degenerative changes in the tubular epithelium which may lead to discharge of calcific material into the lumina.