PRELIMINARY STUDIES WITH THE SENSITIVE CYTOCHEMICAL ASSAY FOR PARATHYROID HORMONE

Abstract

SUMMARY A modification of the cytochemical assay for parathyroid hormone (PTH) is described which permits the measurement of as little as 0.1 fg ml ‐1 . Using this assay circulating concentrations in normal humans range between 1 and 30 pg ml ‐1 using a bovine PTH standard. Elevated values are found in hyperparathyroidism with reduced concentrations in hypoparathyroidism. Where detectable, PTH concentrations measured by radioimmunoassay are on average fourteen‐fold higher than by cytochemical assay. No cross reactivity was found with AVP, calcitonin and 1,25 dihydroxy vitamin D in concentrations normally found in health or disease.