Details

Autor(en) / Beteiligte

• Centeno, V.A
• Diaz de Barboza, G.E
• Marchionatti, A.M
• Alisio, A.E
• Dallorso, M.E
• Nasif, R
• Tolosa de Talamoni, N.G

Titel

Dietary calcium deficiency increases Ca2+ uptake and Ca2+ extrusion mechanisms in chick enterocytes

Ist Teil von

• Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 2004-10, Vol.139A (2), p.133-141

Ort / Verlag

United States

Erscheinungsjahr

2004

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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 γ-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.