TY - JOUR
T1 - Ablation of calcitonin/calcitonin gene-related peptide-α impairs fetal magnesium but not calcium homeostasis
AU - McDonald, Kirsten R.
AU - Fudge, Neva J.
AU - Woodrow, Janine P.
AU - Friel, James K.
AU - Hoff, Ana O.
AU - Gagel, Robert F.
AU - Kovacs, Christopher S.
PY - 2004/8
Y1 - 2004/8
N2 - We used the calcitonin/calcitonin gene-related peptide (CGRP)-α gene knockout model (Ct/Cgrp null) to determine whether calcitonin and CGRPα are required for normal fetal mineral homeostasis and placental calcium transfer. Heterozygous (Ct/Cgrp+/-) and Ct/Cgrp null females were mated to Ct/Cgrp+/- males. One or two days before term, blood was collected from mothers and fetuses and analyzed for ionized Ca, Mg, P, parathyroid hormone (PTH), and calcitonin. Amniotic fluid was collected for Ca, Mg, and P. To quantify skeletal mineral content, fetuses were reduced to ash, dissolved in nitric acid, and analyzed by atomic absorption spectroscopy for total Ca and Mg. Placental transfer of 45Ca at 5 min was assessed. Ct/Cgrp null mothers had significantly fewer viable fetuses in utero compared with Ct/Cgrp+/- and wild-type mothers. Fetal serum Ca, P, and PTH did not differ by genotype, but serum Mg was significantly reduced in null fetuses. Placental transfer of 45Ca at 5 min was normal. The calcium content of the fetal skeleton was normal; however, total Mg content was reduced in Ct/Cgrp null skeletons obtained from Ct/Cgrp null mothers. In summary, maternal absence of calcitonin and CGRPα reduced the number of viable fetuses. Fetal absence of calcitonin and CGRPα selectively reduced serum and skeletal magnesium content but did not alter ionized calcium, placental calcium transfer, and skeletal calcium content. These findings indicate that calcitonin and CGRPα are not needed for normal fetal calcium metabolism but may regulate aspects of fetal Mg metabolism.
AB - We used the calcitonin/calcitonin gene-related peptide (CGRP)-α gene knockout model (Ct/Cgrp null) to determine whether calcitonin and CGRPα are required for normal fetal mineral homeostasis and placental calcium transfer. Heterozygous (Ct/Cgrp+/-) and Ct/Cgrp null females were mated to Ct/Cgrp+/- males. One or two days before term, blood was collected from mothers and fetuses and analyzed for ionized Ca, Mg, P, parathyroid hormone (PTH), and calcitonin. Amniotic fluid was collected for Ca, Mg, and P. To quantify skeletal mineral content, fetuses were reduced to ash, dissolved in nitric acid, and analyzed by atomic absorption spectroscopy for total Ca and Mg. Placental transfer of 45Ca at 5 min was assessed. Ct/Cgrp null mothers had significantly fewer viable fetuses in utero compared with Ct/Cgrp+/- and wild-type mothers. Fetal serum Ca, P, and PTH did not differ by genotype, but serum Mg was significantly reduced in null fetuses. Placental transfer of 45Ca at 5 min was normal. The calcium content of the fetal skeleton was normal; however, total Mg content was reduced in Ct/Cgrp null skeletons obtained from Ct/Cgrp null mothers. In summary, maternal absence of calcitonin and CGRPα reduced the number of viable fetuses. Fetal absence of calcitonin and CGRPα selectively reduced serum and skeletal magnesium content but did not alter ionized calcium, placental calcium transfer, and skeletal calcium content. These findings indicate that calcitonin and CGRPα are not needed for normal fetal calcium metabolism but may regulate aspects of fetal Mg metabolism.
KW - Fetus
KW - Mineral homeostasis
KW - Placental calcium transfer
KW - Skeletal mineralization
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U2 - 10.1152/ajpendo.00023.2004
DO - 10.1152/ajpendo.00023.2004
M3 - Article
C2 - 15039145
AN - SCOPUS:2942542348
SN - 0193-1849
VL - 287
SP - E218-E226
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 2 50-2
ER -