Abnormal parathyroid function in the X-linked hypophosphatemic mouse.

Published

Journal Article

Employing a cytochemical bioassay, we compared parathyroid function in normal and X-linked hypophosphatemic (Hyp) mice. Under basal conditions Hyp mice manifested hypocalcemia and, in accord, had a plasma bioactive parathyroid hormone concentration (3.04 +/- 0.14 pg/ml) significantly greater than that of normals (2.16 +/- 0.14 pg/ml). We confirmed the validity of the bioassay by demonstrating that the plasma collected from both mouse models diluted parallel to the assay standard curve. Moreover, after parathyroidectomy, normal and Hyp mice had plasma bioactive parathyroid hormone levels approximately 90% less than those obtained under basal conditions and indistinguishable from one another. In further studies we observed that dietary calcium and/or vitamin D deprivation in both animal models resulted in a comparable decline of the plasma calcium concentration. However, the concordant increase of the circulating bioactive parathyroid hormone level was greater in the normal mice. Thus, the bioactive parathyroid hormone concentration obtained in response to a low calcium challenge in normals was significantly greater than that in Hyp mice. In contrast, in response to dietary calcium loading, the plasma bioactive parathyroid hormone levels did not decrease significantly from basal values in either animal model. These data illustrate that the bioactive parathyroid hormone concentration in both normal and Hyp mice is inversely correlated with the plasma calcium. However, while the Hyp mice maintain an elevated plasma parathyroid hormone concentration under basal conditions (in response to a decreased plasma calcium), the parathyroid activity of the mutants after a more severe hypocalcemic challenge is attenuated, resulting in a significantly different model of linear correlation. Thus, these data indicate that Hyp mice manifested abnormal regulation of parathyroid function.

Full Text

Duke Authors

Cited Authors

  • Posillico, JT; Lobaugh, B; Muhlbaier, LH; Drezner, MK

Published Date

  • July 1, 1985

Published In

Volume / Issue

  • 37 / 4

Start / End Page

  • 418 - 422

PubMed ID

  • 3930040

Pubmed Central ID

  • 3930040

Electronic International Standard Serial Number (EISSN)

  • 1432-0827

International Standard Serial Number (ISSN)

  • 0171-967X

Digital Object Identifier (DOI)

  • 10.1007/bf02553712

Language

  • eng