TY - JOUR
T1 - Dietary calcium deficiency increases Ca2+ uptake and Ca 2+ extrusion mechanisms in chick enterocytes
AU - Centeno, Viviana A.
AU - Díaz De Barboza, Gabriela E.
AU - Marchionatti, Ana M.
AU - Alisio, Arturo E.
AU - Dallorso, Maria E.
AU - Nasif, Renée
AU - Tolosa De Talamoni, Nori G.
N1 - Funding Information:
This work was supported by grants from FONCYT (PICT 9805-03126), SECYT (UNC) and CONICET (PIP 98), Argentina. Dr. Nori Tolosa de Talamoni is a member of the Investigator Career from the CONICET. Viviana Centeno is a recipient fellowship from FONCYT.
PY - 2004/10
Y1 - 2004/10
N2 - 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 Ca 2+ 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.
AB - 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 Ca 2+ 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.
KW - Alkaline phosphatase
KW - Calcitriol
KW - Chick
KW - Villus tip/crypt axis
KW - Vitamin D receptor
UR - http://www.scopus.com/inward/record.url?scp=7444240811&partnerID=8YFLogxK
U2 - 10.1016/j.cbpb.2004.08.002
DO - 10.1016/j.cbpb.2004.08.002
M3 - Article
C2 - 15528161
AN - SCOPUS:7444240811
SN - 1095-6433
VL - 139
SP - 133
EP - 141
JO - Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
JF - Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
IS - 2
ER -