Between 1973 and 1992, 300 patients underwent
parathyroidectomy for
secondary hyperparathyroidism due to
chronic renal failure in our departments. Using parathyroid glands obtained at operation, histopathological studies were performed, and to estimate pathophysiology
DNA analysis of parathyroid cell nuclei and
calcium-regulated
parathyroid hormone (PTH) secretion in vitro were estimated. PTH
mRNA expression was evaluated by in situ hybridization. The typical histopathological findings were asymmetric enlargement, nodularities and increased number of oxyphil cells. Secondary
hyperplasia was divided into 2 types: diffuse and nodular type
hyperplasia. In the histopathological study nodular
hyperplasia indicated more aggressive proliferation. In
DNA analysis the relative number of scattered cells in the
DNA synthesis phase was significantly greater in nodular than in diffuse
hyperplasia. The half of the maximal inhibition of PTH secretion for
calcium (the set-point) in the cells from nodular
hyperplasia was higher than in the cells obtained from diffuse
hyperplasia. However, there was no difference in expression of PTH
mRNA in nodular and diffuse
hyperplasia. These data suggested that nodular
hyperplasia was more progressively hyperplastic, had more aggressive proliferative activities and showed more abnormal regulation of PTH secretion. These results imply that to prevent graft-dependent recurrent
hyperparathyroidism after
parathyroidectomy, the nodular hyperplastic tissue should not be autografted.