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Updated: Oct 16, 2026

Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy
Published on: July 14, 2023
Calcium stimulates parathyroid hormone-related protein production in Leydig tumor cells through a putative
N Buchs1, D Manen, J P Bonjour
1Division of Bone Diseases, WHO Collaborating Center for Osteoporosis and Bone Diseases, Department of Internal Medicine, University Hospital of Geneva, 1211 Geneva 14, Switzerland.
Abstract:
The production of parathyroid hormone-related protein (PTHrP) is regulated by a variety of hormones and growth factors. Previous research has shown that several PTHrP-producing cells are influenced by extracellular calcium (Ca(2+)(o)) concentration, with elevated levels increasing PTH-like activity released by cultured H500 rat Leydig tumor cells through a post-transcriptional mechanism. We have investigated the hypothesis that calcium stimulates PTHrP production in H500 cells by interacting with a cell membrane-associated cation-sensing receptor. Besides increased Ca(2+)(o) concentration, magnesium and the polycationic antibiotic neomycin also increased PTHrP production in a concentration-dependent manner. In the presence of the calcium ionophore, ionomycin, which markedly elevated cytosolic free calcium, the stimulation by Ca(2+)(o) of PTHrP could still be detected. These results indicate that increasing Ca(2+)(o) stimulates PTHrP production, possibly through a putative cell membrane-associated calcium-sensing mechanism. RT-PCR revealed the presence of a very small amount of calcium-sensing receptor coding mRNA.
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