| Autor: |
Centeno VA; Laboratorio de Metabolismo Fosfocálcico y Vitamina D 'Dr. F. Cañas', Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina., Díaz de Barboza GE, Marchionatti AM, Alisio AE, Dallorso ME, Nasif R, Tolosa de Talamoni NG |
| Jazyk: |
angličtina |
| Zdroj: |
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology [Comp Biochem Physiol A Mol Integr Physiol] 2004 Oct; Vol. 139 (2), pp. 133-41. |
| DOI: |
10.1016/j.cbpb.2004.08.002 |
| Abstrakt: |
Ca2+ uptake and Ca2+ extrusion mechanisms were studied in enterocytes with different degree of differentiation from chicks adapted to a low Ca2+ diet as compared to animals fed a normal diet. Chicks adapted to a low Ca2+ diet presented hypocalcemia, hypophosphatemia and increased serum 1,25(OH)2D3 and Ca2+ absorption. Low Ca2+ diet increased the alkaline phosphatase (AP) activity, independently of the cellular maturation, but it did not alter gamma-glutamyl-transpeptidase activity. Ca2+ uptake, Ca2+-ATPase and Na(+)/Ca2+ exchanger activities and expressions were increased by the mineral-deficient diet either in mature or immature enterocytes. Western blots analysis shows that vitamin D receptor (VDR) expression was much higher in crypt cells than in mature cells. Low Ca2+ diet decreased the number of vitamin D receptor units in both kinds of cells. In conclusion, changes in Ca2+ uptake and Ca2+ extrusion mechanisms in the enterocytes by a low Ca2+ diet appear to be a result of enhanced serum levels of 1,25(OH)2D3, which would promote cellular differentiation producing cells more efficient to express vitamin D dependent genes required for Ca2+ absorption. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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