The secretion of radioactive peptides by dispersed porcine parathyroid cells incubated with [3H]- or [14C]amino acids, [3H]glucosamine and [3H]mannose was analyzed. After incubation, the culture medium contained radioactive parathormone, as expected, and two radioactive glycopeptides: SP I and SP II. SP I appears to be identical with parathyroid secretory protein, heretofore not recognized as a glycoprotein. SP II has not been previously identified. SP I, but not SP II or parathormone, was adsorbed by Concanavalin A possibly reflecting a high mannose content of this molecule. Raising the concentration of calcium in the medium suppressed the secretion of radioactive parathormone and SP I in a similar fashion but did not affect the secretion of SP II. Our results suggest that SP I may play a fundamental role in parathyroid synthetic or secretory processes.
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jun 29 1978|