Regulation of function of transplanted parathyroid glands in man

The results of studies performed in nine patients who had undergone successful parathyroidectomy and gland transplantation are presented. Transplantation of parathyroid tissue to the forearm, performed for therapeutic reasons, provided a unique opportunity to sample parathyroid gland effluent and to assess secretory function in vivo. The relationship of calcium to immunoreactive parathyroid hormone (iPTH) release was studied during calcium and ethylenediamine tetraacetic acid (EDTA) infusions as well as dialysis against a low calcium bath (low calcium dialysis) in patients with chronic renal failure. Calcium infusions caused an abrupt decrease in hormone release down to a persistent base line within 30 minutes, whereas EDTA infusion caused a sharp increase which peaked between 30 to 60 minutes and returned towards base line despite continuation of the hypocalcemic stimulus. Low calcium dialysis caused an irregular release of hormone which appeared to deplete gland reserves during the period of the stimulus. Ready access to the venous effluent of the transplanted tissue makes this an excellent model for studying parathyroid physiology in man.