The reduced responsiveness of cultured bovine parathyroid cells to extracellular Ca2+ is associated with marked reduction in the expression of extracellular Ca(2+)-sensing receptor messenger ribonucleic acid and protein.
Endocrinology
; 136(7): 3087-92, 1995 Jul.
Article
en En
| MEDLINE
| ID: mdl-7789335
PTH secretion from dispersed bovine parathyroid cells maintained in culture becomes progressively less responsive to changes in the extracellular Ca2+ concentration (Ca2+o) over several days. We have now investigated whether this change in secretory control is associated with alterations in the expression of the Ca2+o-sensing receptor (BoPCaR) recently cloned from bovine parathyroid, which plays a central role in Ca2+o-regulated PTH secretion. BoPCaR messenger RNA levels dropped rapidly in cultured bovine parathyroid cells, as assessed by Northern analysis, decreasing by 78% within 18 h and remaining low for at least 4 days. The level of receptor protein decreased to a comparable extent (approximately 72-82%) after 3-4 days in culture, as determined by immunocytochemistry with specific antibodies directed at the extracellular domain of the receptor. The half-time for the reduction in receptor protein (approximately 2 days) was considerably longer, however, than that for BoPCaR messenger RNA, but was comparable to that for the loss of sensitivity of PTH secretion to Ca2+o. Indeed, there was a close linear correlation between maximal suppressibility of PTH secretion and the intensity of staining for the receptor protein (r = 0.88; P = 0.004). We conclude that alterations in the expression of BoPCaR could explain much of the reduced responsiveness of cultured bovine parathyroid cells to Ca2+o.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Glándulas Paratiroides
/
ARN Mensajero
/
Expresión Génica
/
Calcio
/
Receptores de Superficie Celular
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Endocrinology
Año:
1995
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos