Subcellular location of human parathyroid hormone immunoreactive peptides and preliminary evidence for a precursor to human PTH-1 (38545).

In 1963, Berson, Yalow, Aurbach and Potts reported the development of a radio-immunoassay for parathyroid hormone (PTH) (1). Even though this tool has been available for several years, the nature of the processes of synthesis, storage and secretion of PTH is incompletely understood. Evidence of a possible precursor in the biosynthesis of PTH has been shown by both Cohn et al. (2) and Kemper et al. in the cow (3), and by Habener et al. (4) and Chu et al. (5), in the human.This communication will show evidence for the existence of multiple immunoreactive human PTH polypeptides in parathyroid glands, two of which appear to be larger than the previously described precursors to PTH. Furthermore, we will show the intracellular location of these polypeptides. These data provide a basis for formulation of a hypothesis that may explain the interrelationships of these polypeptides.Methods. Preparation of subcellular fractions. The subcellular distribution of immunorea ctive PTH (iPTH) was studied in human parathyro...