Column chromatography of human serum parathyroid immunoreactive peptides.

Abstract

Recently various reports have appeared attempting to define the size of serum parathyroid hormone (PTH). Canterbury and Reiss have shown that their assay measured, predominantly, a peptide of about 7000 mol wt and less of those peptides with 9500 and 5000 mol wt (1). They show, however, that the 9500 mol wt peptide is sensitive to calcium perturbation and decays rapidly after parathyroidectomy. Habener et al. (2) showed evidence that 9500 mol wt PTH is secreted and concluded that peripheral cleavage results in a 7000 mol wt peptide being predominant in peripheral serum. Martin et al. (3) have shown in monolayer cultures of human parathyroid glands that a peptide similar to beef PTH is secreted. Arnaud et al. (4) showed evidence that both 7000 and 9500 mol wt peptides are present in uremic serum and parathyroid adenomas, and concluded that the former peptide is a better steady state indicator or parathyroid dysfunction while the large form is related to acute changes of parathyroid function. In this communication we will show evidence that uremic serum has principally a peptide of 10,000 mol wt and that, in contrast, the pattern of serum PTH peptides from patients with parathyroid adenomas can be quite variable. These data support the hypothesis presented previously, relating to the synthesis and secretion of human parathyroid hormone (5). Methods. Measurement of parathyroid hormone. An antibody to beef parathyroid hormone was prepared in chickens by injecting them for 9 mo with 75% pure beef PTH of 9500 mol wt. The antibody recognizes the intact beef PTH molecule but does not recognize the N-terminal 1-34 segment of beef PTH. This antibody is unique in that it is multivalent in its ability to recognize a number of human parathyroid peptides ranging from > 25,000 to 3000 mol wt (5).