CASE OF A PARATHYROIDECTOMIZED PATIENT OBSERVED LONGITUDINALLY BY ULTRASONOGRAPHY - RELATIONSHIP BETWEEN THE GROWTH-RATES AND 1,25-DIHYDROXYVITAMIN D-3 RECEPTOR CONTENTS IN THE PARATHYROID-GLANDS

Parathyroid glands enlarge gradually with the progression of secondary hyperparathyroidism. The significance of down-regulation of the 1,25- dihydroxyvitamin D receptor (VDR) in parathyroid glands has been empha sized. Here we report a case in whom the relationship between the grow th rates of the parathyroid glands and their VDR content was examined. A 36-year-old man, who had been hemodialyzed for 8.8 years because of chronic renal failure due to chronic glomerulonephritis, developed se vere secondary hyperparathyroidism. The first ultrasonographic examina tion of the parathyroid glands, performed 10 months before parathyroid ectomy, revealed that the sizes of the right upper (RU) and left upper (LU) glands were 10 x 8 x 5 and 14 x 10 x 9 mm(3), respectively, alth ough the right lower (RL) and left lower (LL) glands were not detected . The second ultrasonographic examination performed 5 days before PTX revealed that the RU gland had enlarged up to 24 x 12 x 10 mm(3), whil e the LU gland remained unchanged at 16 x 9 x 8 mm(3). At this time, t he sizes of the RL and LL glands were determined only in the longitudi nal section to be 10 x 5 and 4 x 3 mm(2), respectively. In the excised specimens, the sizes and weights of the RU and RL glands were 25 x 10 x 9 mm(3) and 1,950 mg and 17 x 10 x 8 mm(3) and 1,160 mg, respective ly, while those of the LU and LL glands were 16 x 10 x 7 mm(3) and 850 mg and 9 x 8 x 7 mm(3) and 350 mg, respectively. Histopathologic stud y demonstrated that the RU and RL glands exhibited nodular hyperplasia , while the LU and LL glands exhibited diffuse hyperplasia. Using a li gand binding assay, the VDR content of the rapidly growing RU and RL g lands were significantly reduced to 32.6 +/- 9.6 and 32.7 +/- 5.2 fmol /mg protein, respectively, as compared to that of the LU gland with no significant proliferating activity (111.8 +/- 0.8 fmol/mg protein). I t is of great interest that the smallest LL gland, which showed some p roliferating potential in spite of a histologic pattern of diffuse hyp erplasia, has a VDR content of 41.0 +/- 2.6 fmol/mg protein. In summar y, it was implied from this case that the VDR content in the parathyro id gland might reduce as the growth rate of the parathyroid gland incr eases and, furthermore, that the VDR content seems to depend to some d egree on the histopathologic pattern rather than on gland weight.