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Persistence of Ca 2+ ‐Sensing Receptor Expression in Functionally Active, Long‐Term Human Parathyroid Cell Cultures
Author(s) -
Roussanne MarieCécile,
Gogusev Jean,
Hory Bernard,
Duchambon Patricia,
Souberbielle Jean Claude,
Nabarra Bernadette,
Pierrat Denise,
Sarfati Emile,
Drüeke Tilman,
Bourdeau Agnès
Publication year - 1998
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.1998.13.3.354
Subject(s) - parathyroid chief cell , parathyroid hormone , extracellular , receptor , medicine , endocrinology , hyperparathyroidism , immunocytochemistry , cell culture , biology , western blot , secretion , microbiology and biotechnology , chemistry , calcium , biochemistry , gene , genetics
An original human parathyroid cell culture model from uremic patients with II° hyperparathyroidism has been developed, with its main feature being long‐term functionally active viability up to 5 months, as assessed by persistent responsiveness to changes of extracellular Ca 2+ concentrations ([Ca 2+ ] e ). In addition to the inhibitory effect of increasing [Ca 2+ ] e , increasing extracellular phosphate exerted a biphasic effect on parathyroid hormone (PTH) secretion. The presence of the Ca 2+ ‐sensing receptor (CaR), on which depends the response to [Ca 2+ ] e and its persistence, has been demonstrated in our culture system both by direct detection and by inhibition of its activity. CaR protein was detected by Western blot analysis with a specific anti‐CaR antibody. CaR gene transcripts have been identified by reverse transcription‐polymerase chain reaction analysis. mRNA (by in situ hybridization) and protein (by immunocytochemistry) expression were detected for both CaR and PTH. Adding a specific anti‐CaR antibody to the medium induced a marked reduction of low [Ca 2+ ] e ‐stimulated PTH release, which decreased to levels equivalent to those obtained in high [Ca 2+ ] e medium. The described long‐term functionality could be due to several factors, including the clustered cell type of culture yielded by our preparation procedure, the growth characteristics of hyperplastic uremic tissue, and the use of a phosphate‐rich medium. The present model, because of its long‐term functionality, is a unique tool for the exploration of PTH synthesis and secretion and for studies of parathyroid cell growth in vitro.