Parathyroid hormone-parathyroid hormone-related peptide receptor expression and function in otosclerosis

• Published in: American journal of physiology: endocrinology and metabolism 1999-12, Vol.277 (6), p.E1005-E1012
• Main Authors: Grayeli, Alexis Bozorg, Sterkers, Olivier, Roulleau, Pierre, Elbaz, Pierre, Ferrary, Evelyne, Silve, Caroline
• Format: Article
• Language: English
• ISSN: 0193-1849; 1522-1555
• DOI: 10.1152/ajpendo.1999.277.6.E1005

1  Institut National de la Santé et de la Recherche Médicale Unité 426, Faculté Xavier Bichat, Université Paris 7, 75018 Paris; 2  Service d'Otorhinolaryngologie, Hôpital Beaujon, Assistance Publique-Hôpitau de Paris, 92118 Clichy; 3  Service d'Otorhinolaryngologie Department, Hôpital Necker, Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris; and 4  Service d'Otorhinolaryngologie, Fondation Adolphe de Rothschild, 75012 Paris, France The aim of this study was to investigate the possibility that an abnormality related to parathyroid hormone (PTH) action is involved in the increased bone turnover observed in otosclerosis. To do so, expression and function of the PTH-PTH-related peptide (PTHrP) receptor were studied in the involved tissue (stapes) and compared with that in control bone sample obtained from the external auditory canal (EAC) in the same patient in 10 cases of otosclerosis and in 1 case of osteogenesis imperfecta. PTH-PTHrP receptor expression was studied by RT-PCR of RNA prepared from cultured cells in three patients and RNA directly extracted from bone samples in four patients. PTH-PTHrP receptor function was assessed by measuring the stimulation of cAMP production by 0.8,   8, and 80 nM PTH in bone cell cultures in seven cases. Results showed that PTH-PTHrP receptor mRNA expression in the otosclerotic stapes was lower than that in EAC samples ( P