Secretory disturbance in hyperplastic parathyroid nodules of uremic hyperparathyroidism: Implication for parathyroid autotransplantation

Pathophysiological characteristics of dispersed parathyroid cells were investigated in vitro with the principal aim of examining dominating hyperplastic parathyroid nodules in uremia. Ten large nodules were macroscopically dissected from the glands of 8 hypercalcemic patients with uremic hyperparathyroidism (HPT). Histologic examination revealed that the remaining parts of these glands were composed of a diffuse or slightly nodular parathyroid hyperplasia. Parathyroid hormone (PTH) concentrations were estimated with a mid‐C regional immunoassay and the calcium indicator quin‐2 was utilized to measure cytoplasmic calcium concentrations (Ca 2+ i ) of the parathyroid cells. Ambient calcium control of PTH release and Ca 2+ i was significantly more abnormal in cells from the nodules while the less nodular tissue demonstrated a regulation similar to normal bovine parathyroid cells. Since an aberrant secretory regulation of the parathyroid tissue has been shown to greatly influence serum calcium concentrations in HPT, the findings substantiate a functional importance of hyperplastic parathyroid nodules in uremia. The results imply that parathyroid autotransplants should be excised from essentially nonnodular parts of the parathyroid glands since this may reduce the incidence of graft‐dependent recurrences after total parathyroidectomy in uremic HPT.