Effects of minor increase in serum calcium on the immunoheterogeneity of parathyroid hormone in healthy subjects and in patients with primary hyperparathyroidism
(1995) In Hormone Research 43(6). p.9-294- Abstract
To study possible influences of a mild increase in serum-ionized calcium concentration that is seen during daily life on circulating parathyroid hormone (PTH) immunoheterogeneity, we used sequence-specific PTH assays to determine serum intact PTH, C-terminal PTH and N-terminal PTH following oral calcium (1.5 g) in healthy subjects (n = 7). This was also performed in patients with primary hyperparathyroidism (pHPT; n = 10) to see if their regulation of circulating PTH molecular forms is normal. Compared to healthy subjects, the patients were hypercalcemic (p < 0.05) and had higher levels of PTH in all three assays (p < 0.001). Following the oral calcium load, serum-ionized calcium increased by 0.08 +/- 0.03 mmol/l in the patients... (More)
To study possible influences of a mild increase in serum-ionized calcium concentration that is seen during daily life on circulating parathyroid hormone (PTH) immunoheterogeneity, we used sequence-specific PTH assays to determine serum intact PTH, C-terminal PTH and N-terminal PTH following oral calcium (1.5 g) in healthy subjects (n = 7). This was also performed in patients with primary hyperparathyroidism (pHPT; n = 10) to see if their regulation of circulating PTH molecular forms is normal. Compared to healthy subjects, the patients were hypercalcemic (p < 0.05) and had higher levels of PTH in all three assays (p < 0.001). Following the oral calcium load, serum-ionized calcium increased by 0.08 +/- 0.03 mmol/l in the patients and by 0.07 +/- 0.03 mmol/l in the healthy subjects after 90 min, whereas serum intact PTH, C-terminal PTH and N-terminal PTH were reduced, both in the healthy subjects and in the patients. Suppression by calcium of both intact PTH and C-terminal PTH were impaired in the patients (p < 0.05 and p < 0.001), whereas suppression of N-terminal PTH was normal. Furthermore, the C/i and N/i ratios were higher at the highest calcium concentration achieved after calcium intake in the healthy subjects than in the basal state in the patients (p < 0.05), in spite of the larger degree of hypercalcemia in the latter (1.40 +/- 0.06 vs. 1.31 +/- 0.02 mmol/l; p < 0.05). Thus, (1) a minor increase in serum-ionized calcium that is seen during daily life alters the relative circulating concentrations of PTH versus its fragments; (2) the impaired sensitivity to calcium in pHPT is not evident for the suppression of N-terminal PTH, and (3) pHPT is accompanied by altered immunoheterogeneity of circulating PTH.
(Less)
- author
- Ahrén, B LU and Bergenfelz, A LU
- organization
- publishing date
- 1995
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Calcium, Female, Humans, Hyperparathyroidism, Immunoassay, Kinetics, Male, Middle Aged, Parathyroid Hormone, Peptide Fragments, Journal Article, Research Support, Non-U.S. Gov't
- in
- Hormone Research
- volume
- 43
- issue
- 6
- pages
- 6 pages
- publisher
- Karger
- external identifiers
-
- pmid:7607615
- scopus:0029020206
- ISSN
- 0301-0163
- language
- English
- LU publication?
- yes
- id
- 32cf3d7d-5ace-47f7-b6ac-525ac001fd1d
- date added to LUP
- 2017-05-10 17:42:21
- date last changed
- 2024-01-13 20:43:37
@article{32cf3d7d-5ace-47f7-b6ac-525ac001fd1d, abstract = {{<p>To study possible influences of a mild increase in serum-ionized calcium concentration that is seen during daily life on circulating parathyroid hormone (PTH) immunoheterogeneity, we used sequence-specific PTH assays to determine serum intact PTH, C-terminal PTH and N-terminal PTH following oral calcium (1.5 g) in healthy subjects (n = 7). This was also performed in patients with primary hyperparathyroidism (pHPT; n = 10) to see if their regulation of circulating PTH molecular forms is normal. Compared to healthy subjects, the patients were hypercalcemic (p < 0.05) and had higher levels of PTH in all three assays (p < 0.001). Following the oral calcium load, serum-ionized calcium increased by 0.08 +/- 0.03 mmol/l in the patients and by 0.07 +/- 0.03 mmol/l in the healthy subjects after 90 min, whereas serum intact PTH, C-terminal PTH and N-terminal PTH were reduced, both in the healthy subjects and in the patients. Suppression by calcium of both intact PTH and C-terminal PTH were impaired in the patients (p < 0.05 and p < 0.001), whereas suppression of N-terminal PTH was normal. Furthermore, the C/i and N/i ratios were higher at the highest calcium concentration achieved after calcium intake in the healthy subjects than in the basal state in the patients (p < 0.05), in spite of the larger degree of hypercalcemia in the latter (1.40 +/- 0.06 vs. 1.31 +/- 0.02 mmol/l; p < 0.05). Thus, (1) a minor increase in serum-ionized calcium that is seen during daily life alters the relative circulating concentrations of PTH versus its fragments; (2) the impaired sensitivity to calcium in pHPT is not evident for the suppression of N-terminal PTH, and (3) pHPT is accompanied by altered immunoheterogeneity of circulating PTH.</p>}}, author = {{Ahrén, B and Bergenfelz, A}}, issn = {{0301-0163}}, keywords = {{Calcium; Female; Humans; Hyperparathyroidism; Immunoassay; Kinetics; Male; Middle Aged; Parathyroid Hormone; Peptide Fragments; Journal Article; Research Support, Non-U.S. Gov't}}, language = {{eng}}, number = {{6}}, pages = {{9--294}}, publisher = {{Karger}}, series = {{Hormone Research}}, title = {{Effects of minor increase in serum calcium on the immunoheterogeneity of parathyroid hormone in healthy subjects and in patients with primary hyperparathyroidism}}, volume = {{43}}, year = {{1995}}, }