Normal parathyroid hormone responsiveness of bone-derived cells from a patient with pseudohypoparathyroidism

Sophia Ish-Shalom, Letitia G. Rao, Michael A. Levine, Donald Fraser, Sang W. Kooh, Robert G. Josse, Robert Mcbroom, Min Min Wong, Timothy M. Murray

    Research output: Contribution to journalArticle

    Abstract

    Pseudohypoparathyroidism (PHP) is characterized by a lack of response to parathyroid hormone (PTH); however, normal skeletal responsiveness to PTH in some patients with PHP type Ia was previously suggested on the basis of clinical observations. To test this hypothesis, we measured cyclic adenosine monophosphate (cAMP) production in response to various agonists in bone- derived osteoblast-like (OBL) cells from trabecular explants obtained from an iliac crest biopsy of a 25-year-old woman with PHP. The patient was proved to have PHP type Ia on the basis of Albright's hereditary osteodystrophy and decreased activity of stimulatory guanine nucleotide-binding protein (G(s)) in erythrocytes. Responsiveness of the patient's OBL cells was compared with OBL cells from eight subjects aged 18-39 years who bad no evidence of metabolic bone disease. OBL cells from the patient responded to the following agonists (expressed in multiples of elevation of cAMP, stimulated/basal, mean ± SE, n = 3): PTH, 3.8 ± 0.3; forskolin, 8.2 ± 0.2; and cholera toxin, 56.8 ± 10.0. These responses were not significantly different from those of control OBL cells: PTH, 4.5 ± 1.1 (range 2.4-7.5); forskolin, 7.7 ± 1.4; and cholera toxin, 57.9 ± 16.2. The normal cholera toxin response indicated the presence of functional G(s). Bone cells from patients with PHP type Ia may exhibit a normal PTH receptor-coupled adenylyl cyclase system in vitro despite clinical evidence of impaired hormone-responsive adenylyl cyclase in other tissues, including the kidney. Skeletal responsiveness to PTH may explain the long periods of spontaneous normocalcemia observed in this patient.

    Original languageEnglish (US)
    Pages (from-to)8-14
    Number of pages7
    JournalJournal of Bone and Mineral Research
    Volume11
    Issue number1
    StatePublished - Jan 1996

    ASJC Scopus subject areas

    • Surgery

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    Ish-Shalom, S., Rao, L. G., Levine, M. A., Fraser, D., Kooh, S. W., Josse, R. G., Mcbroom, R., Wong, M. M., & Murray, T. M. (1996). Normal parathyroid hormone responsiveness of bone-derived cells from a patient with pseudohypoparathyroidism. Journal of Bone and Mineral Research, 11(1), 8-14.