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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2010-5-3
pubmed:abstractText
Epithelial calcium transport occurs by paracellular and transcellular mechanisms. Transcellular transport in intestinal and renal epithelia involves several transport proteins, including transient receptor potential vanilloid member 5 (TRPV5), member 6 (TRPV6), calbindin D9k (CB9), calbindin D28k (CB28), sodium calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1 (PMCA1), and the vitamin D receptor (VDR). We are interested in the horse because of its unique calcium physiology (high blood calcium, high intestinal calcium absorption, high renal excretion of calcium, low vitamin D concentrations), and because horses often have dysregulated calcium balance with various diseases. We cloned the mRNA for equine TRPV5, TRPV6, CB9, CB28, NCX1, PMCA1, and VDR, performed comparative mRNA and protein sequence analysis, and quantified their mRNA expression in the kidney and gastrointestinal tract. Sequence homology for the mRNAs and proteins was high among mammals (>75%), with fish having the lowest homology (<75%). TRPV5, TRPV6, and CB9 expression was higher in the duodenum and proximal jejunum and followed a similar expression pattern. CB28 expression was greatest in the kidney. PMCA1 and NCX1 expression was similar throughout the intestine, but in the kidney PMCA1 expression was higher. Based on our findings, the proximal small intestine is the main site for transcellular calcium transport, with TRPV6 and CB9 serving as the main transport proteins. In the kidney, TRPV6, CB28, and PMCA1 are likely more important. The low VDR expression in the equine small intestine and kidney relative to the large intestine, together with the reported high intestinal absorption and renal excretion of calcium, and low vitamin D concentrations suggests that epithelial calcium transport in horses is not as dependent on vitamin D as in other species.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1095-6840
pubmed:author
pubmed:copyrightInfo
Copyright 2010 Elsevier Inc. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
167
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6-10
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Cloning, comparative sequence analysis and mRNA expression of calcium-transporting genes in horses.
pubmed:affiliation
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon Tharp Street, Columbus, OH 43210, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't