When immunoreactive human parathyroid hormone (hPTH), extracted by three different solvents (20% acetone in 1% acetic acid, 8 M urea, or normal saline) from parathyroid glandular tissue was subjected to Sephadex G-100 gel filtration and immunoassay using two different antisera (273 and C-329), four distinct fractions were observed. The first (I), a void volume peak, was detected by both antisera with similar immunoreactivity, as was a second (II), which had the elution and sedimentation properties of highly purified bovine parathyroid hormone (bPTH); a third (III) eluted between [125I]growth hormone and [125I]insulin, sedimented with the velocity of a molecule of approximately 6,000 mol wt, and was detected primarily by antiserum 273; a final fraction (IV), detected primarily by C-329, eluted just prior to [125I]insulin. The elution profiles of the acetone-acetic acid and 8 M urea extracts were similar and contained fraction II as their major component. In saline extracts, however, fraction III predominated.
Robert Silverman, Rosalyn S. Yalow