Expression of the parathyroid Ca(2+)-sensing receptor in cytotrophoblasts from human term placenta.
Fura-2-loaded human cytotrophoblasts responded to elevated extracellular Ca2+ concentration ([Ca2+]o) with monophasic or, in the case of large (> 20 microns) extravillous cells, biphasic elevations in intracellular free Ca2+ ion concentration ([Ca2+]i) that returned to baseline levels after restoration of control [Ca2+]o. Large extravillous cytotrophoblasts also responded to elevated [Mg2+]o with transient elevations in [Ca2+]i, consistent with the behaviour of the parathyroid Ca2(+)-sensing receptor. Expression of the parathyroid Ca2(+)-sensing receptor in placental cells was confirmed using Northern blot and reverse transcription (RT)-PCR analysis. However, the major transcript in human placental cells (6.2 kb) differed from that expressed by human parathyroid cells (5.6 kb). RT-PCR analysis and DNA sequencing of key PCR products also revealed the presence of a splice variant in placental and parathyroid cells that lacks exon 3.
Bradbury
R A
RA
Department of Biochemistry, University of Sydney, New South Wales, Australia.
Sunn
K L
KL
Crossley
M
M
Bai
M
M
Brown
E M
EM
Delbridge
L
L
Conigrave
A D
AD
D015152:Blotting, Northern; D005091:Exons; D005260:Female; D006801:Humans; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis*; D044169:Receptors, Calcium-Sensing; D011956:Receptors, Cell Surface / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014327:Trophoblasts / Q000378:metabolism*
D012333:RNA, Messenger; D044169:Receptors, Calcium-Sensing; D011956:Receptors, Cell Surface